sexagesimal

The article below the hyperlinks is about the sexagesimal of Mesopotamia with was founded by the Sumerians some 6000 years ago. Nothing is known why the Sumerians chose a sexagesimal (base 60) number system, but in this article a hypothesis is presented that has at least some solid proof from Number Theory. According to this hypothesis the sexagesimal was founded because 60 is the number with the most only consecutive factors under SQRT(n). Thus the factor pairs are easy to remember and hence easy to work with. In other words: This makes mental calculations in the sexagesimal very convenient.

 

 

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J.G. van der Galiën ‘The Dawn Of Science’ 1.1. (2002)

Full paper

SATOCONOR.COM Journal of History

 

 

The Dawn Of Science

A New Hypothesis about the Foundation of the Sexagesimal Number System in the cradle of civilisation

By Johan G. van der Galiën

For comments e-mail: johan.van.der.galien@satoconor.com

Version 1.3. September 25, 2005 (version 1.0. from August 13, 2002)

 

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Abstract:

Several old hypotheses, which can be found in the literature and on the Internet, about why the Sumerians took the sexagesimal sytem as their number base are discussed. They all fall in to the categories of factorability, astronomy, combination of earlier number bases or interaction of language with writing. Most of them I will disprove in this publication.

A new hypothesis is presented about an decimal system as starting point used in the period before the early Uruk (> 3500 BC). In this system the Sumerian temple order did resolving of natural numbers in factors. They discovered that 60 is, among the integers (n), the number with the most solely consecutive factors under the breakpoint of factors (√n, see paragraph 2.1.).

In this article the rediscovery of this fact by my self, based on empirical results of a PASCAL program, and the mathematical proof of Dean Hickerson is given.

Because of this unique property of 60 the priest caste, who were in the middle of all economical activities, which took a lot of calculating, regarded 60 as highly mystical. In other words holy, which is illustrated by the fact that there supreme god Anoe was coupled to this number. What might have amplified the opinion of the priest is the fact that because of this consecutive sequence all the factors are easy remembered and consequently easy to work with in mental calculations. That is why, in my opinion, Sumerian economic calculations shifted from a decimal number system to a base 60 (sexagesimal) system!

 

1. Introduction

The deepest root of science is most likely the foundation of the sexagesimal number system widely used by the Mesopotamians. [The Sumerians where the first people to develop a calculating system and during developing of their sexagesimal number base system they must also have discovered the prime numbers for the first time. They must have regarded these strange and odd (prime) numbers as being a problem for (mental) division in their sexagesimal system.] Because of this event we prosper of all the blessings of nowadays science and technology. The sexagesimal astronomical and mathematical clay tablets of Mesopotamian science found its way to classical Greece where a proliferation of this knowledge took place. It spread from there over the rest of the ancient world. But during the middle ages it became forgotten in western Europe. It was not until the crusades that this legacy was rediscovered as translations of the Greek texts in the Arabian language of the battled Islamic cultures. Next it formed the basis of the scientific exploration during the Renaissance in Europe with lead to science, as we know it today!

 

2. Number Theory and 60

2.1. The factorisation of integers and specially that of the number 60

One can resolve all integers in to pairs of so called factors (in this article used as synonym for divisors). Multiplication of the two factors from a pair yields the resolved number. In Table 1 this resolving of the first twelve integers is shown.

 

1=

2=

3=

4=

5=

6=

7=

8=

9=

10=

11=

12=

1*1

1*2

1*3

1*4

2*4

1*5

1*6

2*3

1*7

1*8

2*4

1*9

3*3

1*10

2*5

1*11

1*12

2*6

3*4

 

Table 1: The resolving in factors of the first twelve integers.

 

If one does resolving of factors of integers (n), for instance by means of a computer program like the PASCAL program FACTOR1 (see Appendix), one only has to check the integers for possible factors from 1 up to rounded √n. Because the factors above √n are then already determined. In other words the factor pairs repeat them self above √n in the reverse order. I call √n the breakpoint for factors as you can see below:

 

12=

1*12

2*6

3*4

------Breakpoint √12 ≈ 3,464 rounded = 3

4*3

6*2

12*1

 

It can happen that √n is also a factor of n like in the case of n = 16. √16 = 4 and consequently the corresponding factor pair 4*4 = 16.

Numbers with only one pair of factors (1*n, n being the number it self.) are called prime numbers (p). The prime numbers play an important role in fundamental number theory and for instance in encryption. So the numbers 2, 3, 5, 7 and 11 from Table 1 are prime. The number 1 is not considered prime because of the fundamental theorem of Number Theory which says that each not prime number (composite) has a set of unique prime factors. If the number 1 was prime then one could write infinite sets of prime numbers for a composite because a composite = p1a*p2b*p3c……

R.E. Smalley, the 1996 Nobel Laureate in Chemistry who got this prize for the discovery of the fullerenes (Like the archetypal fullerene C60 also known as the Buckyball.), said in a lecture: "…60 is the most factorable of all integers. That’s why the Babylonians used it as the base of their number system…".1

The number 60 has 12 factors by the way, and they are:

 

60=

1*60

2*30

3*20

4*15

5*12

6*10

 

A simple PASCAL program (See Appendix program: FACTOR1) proofs that there are an infinite amount of numbers with more than 12 factors, take for example 120, a multiple of 60, as you can see below:

 

120=

1*120

2*60

3*40

4*30

5*24

6*20

8*15

10*12

 

120 has 16 factors! But it is not only the multiples of 60 which have more than 12 factors. Take for example the number 1000:

 

1000=

1*1000

2*500

4*250

5*200

8*125

10*100

20*50

25*40

 

1000 also has 16 factors! As a matter of fact; while the numbers grow, so do the amount of possible factors. In my Number Theory research I discovered that the numbers in the 50 millions can have up to 700 factors.2 Take for instance the number 47.345.760 it has 504 factors!

So 60 is NOT the number with the most factors! But what does make 60 so special and different from all the other integers? For this we must look at the fact that all the factors below the square root of 60 (Ö 60 » 7,746) are consecutive from 1 up to 6. I wrote a PASCAL (See Appendix program: SXGSML8) to inspect if there are more numbers with solely consecutive factors under Ö n. I checked all the integers up to 47.345.760 with this program and I found an infinite sequence that includes all the prime numbers (p)14, all the so called "even primes" (2p)15 and the six numbers from Table 2.

 

1=

8=

12=

18=

24=

60=

1*1

1*8

2*4

1*12

2*6

3*4

1*18

2*9

3*6

1*24

2*12

3*8

4*6

1*60

2*30

3*20

4*15

5*12

6*10

 

Table 2: The besides p and 2p additional six numbers with their factors, of the sequence of numbers with solely consecutive factors under Ön. (ID number A066522 On-line Encyclopedia of Integer Sequences16)

 

This sequence is registrated as ID number A066522 at the On-line Encyclopedia of Integer Sequences.16 The first 65 terms of this sequence are 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 17, 18, 19, 22, 23, 24, 26, 29, 31, 34, 37, 38, 41, 43, 46, 47, 53, 58, 59, 60, 61, 62, 67, 71, 73, 74, 79, 82, 83, 86, 89, 94, 97, 101, 103, 106, 107, 109, 113, 118, 122, 127, 131, 134, 137, 139, 142, 146, 149, 151, 157. What immediately becomes clear from the results of the program SXGSML8 is the fact that there are no numbers under 47.345.760 which have more of these consecutive factors than 60. It is even worse; the only numbers, which pass the SXGSML8 criteria above 60, seems to be the primes and the "even primes"! These facts are all empirical! But Dean Hickerson17 has worked out the mathematical proof that only the primes (p), the "even primes" (2p), 1, 8, 12, 18, 24 and 60 have solely consecutive factors under Ö n. (2p has only two pairs of factors they are 1*2p and 2*p.) He argues as follows:17

 

Theorema 2.1.: If n is a positive integer such that the divisors of n which are <= Ön are consecutive integers, then n is either p or 2p with p prime, or n is one of the numbers 1, 8, 12, 18, 24, or 60.

 

Note: It's easy to get lost in the details of the proof, so I'll start by explaining how it works in a special case. Suppose, for example, that the divisors of n that are <= Ön are the numbers 1, 2, ..., 10. Since n is divisible by both 2 and 7, it's divisible by 14. So 14 must be > Ö n, which implies n<196. But n is divisible by 8, 9, and 10, so it's divisible by their least common multiple, lcm(8,9,10)=360. So 360 <= n < 196, which is impossible. Most of the proof consists of showing that we get a similar contradiction if 10 is replaced by any number k>=3. Proof: Let k be the largest divisor of n which is <= Ö n. Thus the divisors of n which are <= Ö n are exactly the integers 1, 2, ..., k, and the divisors of n which are >= Ö n are just n, n/2, ..., n/k.

If k=1, then n has only the divisors 1 and n, so either n=1 or n is prime.

If k=2, then n has only the divisors 1, 2, n/2, and n. If n/2 is not prime, then all of its proper divisors are either 1 or 2, so it must equal 4. Thus either n=8 or n has the form 2p.

So suppose k >= 3. Among the numbers k+1, k+2, k+3, k+4, exactly one is congruent to 2 (mod 4); call this number m. Thus m/2 is an odd number; I claim that it's less than or equal to k. For if not, then k+1 <= m/2 <= (k+4)/2, so k <= 2.

Now we know that both 2 and m/2 are among the numbers 1, 2, ..., k, so they are both divisors of n. Since they are relatively prime, their product, m, must also divide n. Since m > k, m can't be one of the divisors of n that are <= Ö n. Hence Ö n < m <= k+4, so n < (k2+4) .

Next, since n is divisible by all positive integers up to k, it's divisible by the largest 3 of them, k, k-1, and k-2. So n is divisible by lcm(k,k-1,k-2).

By well-known facts about greatest common divisors and least common multiples, we have:

lcm(k-1,k-2) = ((k-1)(k-2))/gcd(k-1,k-2) = (k-1)(k-2),

gcd(k, (k-1)(k-2)) = gcd(k, k(k-3) + 2) = gcd(k,2),

and

lcm(k,k-1,k-2) = lcm(k, lcm(k-1,k-2)) = lcm(k, (k-1)(k-2))

= (k(k-1)(k-2))/gcd(k,(k-1)(k-2)) = (k(k-1)(k-2))/gcd(k,2) = k(k-1)(k-2) or

(k(k-1)(k-2)/2

So

n >= lcm(k,k-1,k-2) >= (k(k-1)(k-2)/2

Combining this with the inequality n < (k+4)2 gives

k(k-1)(k-2) <= 2n < 2(k+4)2.

But this is false for all k >= 8, so we must have k <= 7 and n < (7+4)^2 = 121. So to find all numbers n which have the desired property, we need only check the numbers 1, 2, ..., 120, and we find only the solutions listed in the theorem.

 

The conclusion of my empirical results and the mathematical proof by Dean Hickerson17 is that:

The number 60 has the most only consecutive factors under Ö n of all integers.

This is what makes the number 60 different and unique among the integers. And to come back at the words of Smalley1, it most likely is the reason why the Babylonians used 60 as a base for their number system as I will make clear in paragraph 4.3. (Dean Hickerson is skeptical about this conclusion.) Maybe this and the whole consecutive sequence actually gives a clue to what Smalley owes to the highest factorability of 60. As he puts it:1

"For reasons that so far seem obscure but probably are connected somehow to its high factorability, sixty is also the maximum finite number of ways you can rotate an object around a central point in 3 dimensional space so that when you finish rotating it looks exactly the same as before. Such an object has the symmetry of the icosahedron, the highest finite point group, which has 60 proper rotational symmetry elements."

But that is stuff for another article. Lets first return to the main subject of this article in the next paragraphs.

 

2.2. The different number systems:

A real number can be represented in several ways depending on the so-called number system that is used. The base of these number systems is sometimes called the radix or scale (lets called it b for base). Then using Arabic symbols (0-9) the digits of all real numbers are described by 0, 1, … b-1.4 The number 60 in some of these different number systems (the most used in the world) can be represented as in Table 3.

Decimal is the number system that we use the most in every day live. Telephone numbers, the prizes in the supermarket and the calculations we learn at school are all examples of the use of the decimal number system. But most calculations are done in the binary number system since this is the way that all computers perform their tasks, although the output of a calculation by a computer program is mostly in decimal numbers. Sometimes a programmer or an operator asks for octal or hexadecimal numbers from the computer because these numbers give good insight on what is going on a the binary level, which can be a bit confusing by it self.

 

Base

Name

Systems notation of the decimal number 60

Calculation of the number system notation in to the decimal notation (in other words decimal 60=)

2

Binary

111100

1*25+1*24+1*23+1*22+0*21+0*20

8

Octal

74

7*81+4*80

10

Decimal

60

6*101+0*100

16

Hexadecimal

3C or 3,12

3*161+12*160

60

Sexagesimal

1,0 or 00:01:00 or 0o1’0" or Y

1*601+0*600

 

Table 3: Representation of the decimal number 60 in the most used number systems.

 

You can describe hexadecimal numbers in two ways, as can be seen in Table 1. The first way (method A) comes from the fact that one can count after the 9 up to the decimal symbol 15 with letters from the alphabet. Counting this way from the decimal 1 to 32 in hexadecimal looks like this: 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1A, 1B, 1C, 1D, 1E, 1F, 20 etc. This is the way that the hexadecimal system is used in computer management and programming in assembler. The other way (method B) by convention is to represent it by means of separating the hexadecimal parts, which stand before the different powers of 16 in the calculation of the decimal value (see Table 1), by comma’s. All number systems with a base greater than 10 can be treated in an analogous ways.

At this point I want to introduce a new aspect of number systems: How to represent fractions? By convention placing a comma (in method A) or a semicolon (;) (in method B) between the integer and fractional part and using negative powers of the base to multiply the counter with. For example, the hexadecimal number C57,3A = 12,5,7;3,10 equals 12*162+5*161+7*160+3*16-1+10*16-23159,226562 in the decimal number system.

This brings us, last but not least, to the main subject of this publication: the sexagesimal number system! All the principles stated above also apply to the sexagesimal system. As far as we know it is one of the oldest number system used by mankind, as I will discuss later on. It, partly, survived until today in every day live. For instance we still divide 1 hour in 60 minutes and 1 minute in 60 seconds, although there go 24 hours in 1 day and 365 days in a year, and not 60 hours in 1 day and 60 days in a year as a true sexagesimal time system would require. But this is of course more determined by astronomical phenomena than by the number system used to describe time. The digital clock representation of time 23:06:51 actually means that 23*602+6*601+51*600 = 83211 seconds elapsed since midnight yesterday. It also, partly, survived in what is called the North American system of angular measurement.7 The unit of this system is called a degree (o) which is divided in 60 equal parts, also!, called minutes (‘) which are subdivided into? Yes, 60 seconds ("). But this is as far as the sexagesimal pattern goes, because a circle in this system is exactly 360o and not 60o. Also the fractions of a second are represented in the decimal way! So there is no (’’’) subdivision of a second. I will get back later why a circle is probably defined as 360o in this "sexagesimal" system.

It were the Sumerians, about 5000 years ago, as we soon will discuss in depth, which used the system first and there representation of the decimal number 60, is a so called cuneiform carving in a clay tablet, which looks like the symbol: Y. Because all of this there are 4 system notations for the sexagesimal in Table 1.

We saw in Table 1 how one can calculate numbers from one base system to the decimal system. But how is the method to calculate from one base system to all other possible base systems? My method is to use the decimal systems as an intermediate base. Thus by calculating the base(a) number to a decimal number and calculating this by using so called successive divisions5,6 to the base(b) number. For example calculating the hexadecimal number AC to the ternary system (base = 3) one can proceed like this:

·         Step 1: Calculating AC to the decimal system: 10*161+12*160 = 172

·         Step 2: Calculating 172 to the ternary using successive divisions (div, whole divisions by 3 for base 3) and modulo operations (mod, remainder after a whole division by 3 for base 3):

172 div 3 = 57

172 mod 3 = 1

57 div 3 = 19

57 mod 3 = 0

19 div 3 = 6

19 mod 3 = 1

6 div 3 = 2

6 mod 3 = 0

2 div 3 = 0

2 mod 3 = 2

You proceed with the successive divisions until you encounter a zero for the div operation!

·         Step 3: You arrange the results of the mod operation in reverse order. So hexadecimal AC = decimal 172 = ternary 20101.

·         Step 4 check the results ternary 20101 = 2*34+0*33+1*32+0*31+1*30 = decimal 172 = hexadecimal AC

One can find also another method with uses the binary systems as intermediate base, but the principles are the same.6 I also discovered the interesting mathematical theory behind the method of successive divisions on the internet.6

If I do not mention a number system specifically the numbers are from the decimal system!

 

3. The Sexagesimal of Mesopotamia

3.1. The situation before the sexagesimal place notation:

First I will give a timetable (Table 4) of the Mesopotamian history to put the development of the sexagesimal system in perspective.

 

Notes

Year BC

Period

Writing/Number System Phase

Historical Developments

 

>3500

 

Decimal metrological systems

 

 

3500

 

 

 

 

3400

Early Uruk

Mystical status of 60

 

 

3300

 

Numerical tablets and clay bullae / Sexagesimal metrological systems

Beginning of large scale settlement of Mesopotamia

 

3200

Late Uruk

 

First Urban Centres

Beginning of Proto-Cuneiform

3100

 

Archaic texts from Uruk: Writing Phase Uruk IV

Age of early civilisations

 

3000

Jemdet Nasr

Writing Phase Uruk III

 

Beginning of Proto-Elamite

2900

Early Dynastic I

Archaic texts from Ur

 

Beginning of Hieroglyphics

2800

 

 

Formation of large irrigation networks

 

2700

Early Dynastic II

 

 

 

2600

 

Texts from Fara

 

 

2500

 

 

 

 

2400

 

Old Sumerian texts / Cuneiform sexagesimal place notation

Rival city states

 

2300

Dynasty of Akkad

Old Akkadian texts

First regional states

 

2200

Gudea of Lagash

 

 

 

2100

Ur III

Neo-Sumerian texts

Centralised state of the 3rd Dynasty of Ur

Indus Script

2000

 

 

 

 

1900

Old Assyrian

Old Assyrian texts

 

 

1800

Old Babylonian

Old Babylonian texts

 

 

1700

 

 

Hammurapi of Babylon

 

1600

 

 

 

 

1500

 

 

 

 

1400

 

 

 

 

1300

Middle Assyrian

 

 

 

1200

Kassite

 

Kassite rule

 

1100

 

 

 

 

1000

 

 

 

 

900

 

 

 

 

800

Neo-Assyrian

First Aramaic texts

Assyrian empire

 

700

 

 

Babylonian empire (Nebuchadnezzar II)

 

600

Neo-Babylonian

 

Occupation of Babylon by Cyrus in 539 BC

 

500

Achaemenid

 

 

 

400

Seleucid

Revival of cuneiform under the Seleucids

 

 

Table 4: Timetable of the Mesopotamian history, this is based on work of Nissen et al.18 See also paragraph 4.3. for an explanation of the Number System entries.

 

The so called cuneiform (from the Latin: cuneus, a wedge shape) carvings in clay tablets used for numbers or language, were both created in the same period as we will see later, about 4500 years ago by the Sumerians of Mesopotamia. It is the oldest number system and written language known to mankind. The main theory how this cuneiform based manuscript form evolved is well documented on the internet.8,9 I will here give only a short summary of this material in the next alinea.

The emanation of the cuneiform script happened within a region that is nowadays known as Iraq. There were a lot of emerging civilisations 5000 years ago, but the Sumerians were the first to develop a written language and number system.

Not the need to save a story or poetry was the drive for recording data in the ancient cultures like the Sumerians, but the need to do bookkeeping of economic activities probably was! The first stage of bookkeeping was by means of tokens from stone and later from clay. These tokens represented for instance one jug of wine or one sheep. Remember that the Sumerians not only developed the first written records but also the concept of money in the form of sea shell rings and coins.12,13 This simultaneous development of money and written records is synergistic, and an underestimated important part of Mesopotamian archaeological and anthropological research. But lets say that the early Sumerian culture (4000-3000 BC) had the need to do bookkeeping for commercial purposes without the concept of money. They bartered for instance 3 jugs of wine for 1 sheep and recorded this transaction by putting 3 wine jugs tokens and 1 sheep token in a container (bullae), probably made of clay. A collection of all these containers was their archive of a past transaction or a negotiated contract for in the future. So, in the early stage there were no different signs for quantity and item, they just repeated the sign of the item to the quantity. The problem with these clay containers was that you only knew the content of tokens when you break them, destroying its actual purpose of archiving. So they started to carve the clay envelope with the number of different tokens and with the number of the different signs for what the tokens represent. They developed in time a de facto standard of signs (= tokens = commercial items). A major break through! The second stage begun around 3000 BC because of that economic activities started to grow and become more and more complicated, and one can say also by the introduction of the concept of money because the market got to complicated for bartering!

In the meanwhile Sumerians started to replace the clay envelops + tokens by clay tablets and they developed signs to represent numbers because it became prone to errors to write for instance 100 sheep symbols! On the clay tablet there was in this case the sign for sheep and their notation of the decimal number 100. This break through is called a metrological numeration system. In these early days the whole system was not as advanced as ours by which the 3 can mean 3 sheep, 3 jars of oil or 3 jugs of wine.

They had different metrological numeration’s systems for all possible measures. There was a metrological system for discrete objects, length, area, volumes of different kind of liquids, time and many other measures. Most of these metrological systems where already sexagesimal!18 (See Fig. 3)

So the base 60 of the sexagesimal metrological measuring systems, and finally of the sexagesimal place notation, must have evolved just before this era.

To maintain all of these metrological measure notations was troublesome and the result was one (cuneiform) notation of language and numeration in the sexagesimal system.

 

3.2. The sexagesimal place notation:

In around 2500 BC the cuneiform sexagesimal number system was well established. The representation was based on two symbols: one wedge for ‘1’ (in the text I will use Y for this symbol) and two wedges forming a corner for ‘10’ (in the text I will use < for this symbol). In the source code of CALSEX2 and 3 (see APPENDIX) the principles are shown how to represent the Sumerian numbers 1 – 59. This is in simplified cuneiform notation because the Mesopotamian did grouping of the Y symbols.

What catches the eye of the sexagesimal place notation is the fact that there is no zero and that consequently the signs for 1 and 60 are the same (my notation, an Y). This seems confusing but the Mesopotamians could determine the actual value of an Y symbol from the context. Take for instance the cuneiform notation Y Y <<YY the first Y means 1*60*60, the second Y means 1*60 and <<YY means 22. Using the notation and calculation method of paragraph 2.4. Y Y <<YY means 1,1,22 an this is decimal: 1*602+1*601+22*600 = 3682. With the program CALSEX2 (see APPENDIX) one can calculate how large numbers would be carved in clay tablets by the Mesopotamians. These archaic people did not invent a special symbol for the number zero yet. They often marked a zero column with an empty space:

So 1*602+0*601+1*600 = 3601 would then be marked as Y Y, 1*601+1*600 = 61 would be marked as Y Y and 2*600 = 2 finally would be marked as YY.

But how did Mesopotamians note fractions and numbers with an integer and fraction part? Answer: In the same way as they noted integers! And one must see the distinction, just like as with the lack of a zero mentioned above, through the context of the tablet:

So Y Y <<YY can mean the integer 1*602+1*601+22*600 = 3682 (as I mentioned earlier), the integer/fraction numbers 1*601+1*600+22*60-1 » 61.367 and 1*600+1*60-1+22*60-2 » 1.0228, or the fraction 1*60-1+ 1*60-2 +22*60-3 » 0.01705.

 

3.3. The calculations in the sexagesimal place notation:

And now how the Sumerians did their basic calculations. I will omit the cuneiform notation in this discussion and will use the Arabian numbers. The addition and subtraction operations go analogous as in our decimal system:

Example addition: 59,6,19;4,56 + 3,8;6,5,7 = 59,9,17;11,1,7

Example subtraction: 59,6,19;4,56 – 3,8;6,5,7 = 59,3,9;58,50,53

It can easily be done mentally if you remember that every time you add above 60 or subtract below 0 you have to shift one number to the left in case of adding one to that number. In case of subtracting you have to subtract one from that number.

Multiplication and division are far more complicated in the sexagesimal. If you need to remember 10 multiplication tables (10*10 = 100 facts, which you know from elementary school) in the decimal system, you need to remember 60 (60*60 = 3600 facts) of them in the sexagesimal system!

Because of this problem with mental calculations the Sumerians had developed a workaround for division and multiplication. They used the following formula for multiplication:

(a) xy = [(x+y)2-(x-y)2]/4

To do a quick multiplication they used tables of squares. So they calculated x+y and x-y mentally, looked up the corresponding squares for the answers in a table and finally calculated the multiplication by using the above formula. These squares tables were most likely derived by a tedious addition process where the number of additions were carefully counted, e.g. in the case of 62 by 6+6+6+6+6+6 = 36. It is obscure how the Sumerians derived this formula (a); more research is certainly needed on this topic.

Division was another problem in the sexagesimal related to the need to remember 60 multiplication tables (or 60*60 = 3600 facts) to do it mentally. These archaic people solved it by using the formula:

(b) x/y = x*(1/y)

A division is turned into a multiplication with a reciprocal according to this formula. The Sumerians had also large reciprocal tables on clay tablets. I suppose that the multiplication of an integer and a reciprocal from these tables was also done by formula (a). But this appears to bring in the problem of squaring numbers with a integer part and fraction part with formula (a)! The problem is that they could impossibly have squares tables for all of these occurring numbers. In fact there are an infinite amount of these numbers. I postulate the following hypothesis about this:

"For the Mesopotamians this was not a problem. They handled reciprocals and numbers with an integer and fraction part just like integers in division and multiplication, and interpreted the results according to the context of the starting numbers. In other words they mentally placed the semicolon to separate the integer part from the fraction part of the answer. Lets look at a specific case to illustrate this hypothesis. If a Mesopotamian wanted to divide 1,40 by 25 he would proceed as follows:

1.      Search for the reciprocal of 25 in a table on a clay tablet. He would find 1/25 = 0;2,24, the reciprocal number needed in formula (b)

2.      He would add 1,40 to 2,24 (omitting the semicolon and regard both numbers as integers!) 1,40 + 2,24 = 4,4 in accordance of formula (a)

3.      He would then subtract 1,40 from 2,24 (also regard both numbers as integers) 2,24 – 1,40 = 44 in accordance of formula (a)

4.      As the next step he would look up 4,4 and 44 in a table of squares. He would then find (4,4)2 = 16,32,16 and (44)2 = 32,16 in accordance of formula (a)

5.      He would then subtract the squares 16,32,16 - 32,16 = 16,0,0 in accordance of formula (a)

6.      He then would only have to divide this number by 4 mentally (So he only has to know one multiplication table, the one for 4, to do multiplication’s and divisions) 16,0,0/4 = 4,0,0 in accordance of formula (a)

7.      Finally he would place the "forgotten" semicolon mentally back on its place, that is 2 comma positions to the left. So the answer is sexagesimal 4;0,0 = 4. We can check this number by doing the same calculation in the decimal system. Sexagesimal 1,40 = 1*601+40*600 = 100 decimal and sexagesimal 25 is also 25 decimal. So the decimal answer is 100/25 = 4 which also is the same number in the sexagesimal system as we saw in our answer above!"

A question, which is still open, is: How do the prime numbers, more in general the resolving in factors of integers, look like in the sexagesimal system? In broader sense: Do they have the same decimal value in all number systems? It seems to be so that these arithmetical properties of integers are independent of the base of the number system. So the factors of integers in the sexagesimal have the same decimal value as in the other base system. Thus if this is so for factorability then this also true for the prime numbers!

I have written two PASCAL programs (See Appendix programs: CALSEX2 and CALSEX3) which can be used to test the argumentation’s of this paragraph.

 

4. Hypotheses About the Foundation of the Sexagesimal Number System.

4.1. Hypotheses with can be found in the literature:

To start this chapter I will evaluate the main hypothesis about why some ancient civilisations adopted other number systems than base 60. There is little doubt that ancient civilisations in India (from at least 598 AD) and China (14th century BC) adopted the decimal system (base 10) for anatomical reasons. In other words they had the custom to count on their fingers and this was the basis of their number system!22,23 The Mayans (3rd to 14th century AD) of south America used an vigesimal systems (base 20) also for anatomical reasons, since they were used to count on there fingers and toes.24,25

Now I will say something about the foundation of the sexagesimal number system by the Sumerians, and evaluate the information about this topic, which can be found in the literature. This must be viewed in the light that nothing is known about the exact circumstances of this invention as Nissen et al correctly stated.18 So all the hypotheses about these subject are a shot in the dark! They wait for more scientific evidence from future excavations to be supported or falsified.

The oldest hypothesis is probably the one from Theon of Alexandria (fourth century AD). In his commentary on the first book of the mathematics of Ptolemy he writes as here below where the original Greek text is given. (Which lacks of some of the necessary diactritic symbols. The complete Greek text can be found in the references.19) Along with the English translation:

“… ενχρηστότερον δε πάυτωυ των αριθμων ειναι τον ξ- δια το των αλλων άπάντων των δυναμένων πλείονα μέρη εχειν ελάττονα οντα ενμεταχειριστότερον ειναι”

"… 60 is among all the numbers the most convenient, because being the smallest among all those which have the most divisors, it is the easiest to handle."

George Gheverghese Joseph seems to have found another passage of Theon about this topic because he writes:20

"Different explanations have been offered for the origins of the sexagesimal system, which, unlike base 10, or even base 20, has no obviously anatomical basis. Theon of Alexandria, in the fourth century AD, pointed to the computational convenience of using the base 60. Since 60 is exactly divisible by 2, 3, 4, 5, 6, 10, 15, 20 and 30 [the author omits 12], it becomes possible to represent a number of common fractions by integers, thus simplifying calculations… Indeed, while base 10 maybe more ‘natural’, since we have ten fingers, it is computationally more inefficient than base 60, or even base 12. However, this explanation for the use of base 60 is unconvincing because of its "hindsight" character. It is highly unlikely that such considerations where taken in to account when the base was chosen. A second explanation emphasises the relation that exists between base 60 and numbers that occur in important astronomical quantities.

Joseph goes on to say that either 30, the number of days in a lunar month, or 360, the Babylonians’ consequent estimate of the number of days in the year, was used as the numerical base before the advantages of calculation in base 60 were reconized.21"

The hypothesis, which comes directly from Theon (the Greek text), has been falsified by me in paragraph 2.1. 60 is NOT among the numbers with the most factors, since there are numbers with an infinite amount of factors possible!

The Dutchman Simon Stevin has an similar meaning about the sexagesimal and in his Disme (1585 AD), in which he deals with astronomical computations, he expresses his opinion as follows (given is here the Renaissance French text together with an translation in to Modern English):19,35

"Aians anciens Astronomes parti le circle en 360 degrez, ils voioient que les computations Astronomiques d’ícelles, avec leurs partitions, estoient trop labourieuses pourtant ils ont parti chasque degré en certaines parties, & les mesmes autrefois en autant, &c. à fin de pouuoir par ainsi tousiours operer par nombres entiers, en choisissans la soixantiesme progression, parce que 60 est nombre measurable par plusieurs mesures entieres, à sçauoir 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30."

"Asians Astronomers divided the circle in 360 degrees, so they can do there Astronomical computations with this partitioning, unmature and laborious nevertheless they kept with this burden of dividing the degree in these certain parts (I guess what is mend here is the sexagesimal subdivision of the angular degree.) and this is also true for the division of the circle, et cetera. To end this discussion I bring forward plainly that the number 60 has (I guess that is meant here: many.) many divisors: 1,2, 3, 4, 5, 6, 10, 12, 15, 20, 30."

As I put forward in paragraph 2.1. there are an infinite number of integers with more factors. Thus why didn’t they chose for a base with even more factors?

In his Opera Mathematica, which was published in 1693 AD, J. Wallis finds the reason, for the use of the sexagesimal number system by the ancient world, in the specific arithmetic’s of the number 60. Here below the relevant part of the book in the original Latin text is given, with a sentence for sentence English translation:19,36

"Cur autem voluerint Antiqui fractiones omnes ad unam aliquam denominationem (ut Sexagesimarum) reducere, causa est manifesta;

Why did these Antique people of all possibility’s chose for this number system of measure (in other words the sexagesimal), the cause is detected;

nempe ut molestiam evitarent fractiones vararium denominationum addendi, subducendi, aliasve computandi;

truly resolving factors is difficult in this number system, like adding, like subtracting, in other words calculating

quae certe magna erat, dum numeros majusculos commode tractare non potuerint.

although it (60, in other words the sexagesimal) was great, they did not chose for more inconveniently greater numbers.

Cur autem Sexagesimas prae aliis denominationes elegerint, causa est, Quoniam, si 12 aliumve minutulum numerum pro communi denominatore sumpsissent, pluribus opus foret subdivisionibus, quam sumpto numero 60.

Why is the sexagesimal chosen before other number systems, the reason might lie in the fact, that the former is accepted before other common number systems, in its divisors, of the accepted number 60.

Eo autem multo majorem haud commode tractare potuerunt;

Here we are unable to understand the literature of our ancestors exactly;

cum etiam in hoc satis sit difficultatis.

so we are going to have a difficult venture.

Ex non-majoribus autem, hic caeteris potoir videtur, quoniam plures admittit divisores;

Out of all what is seen seems to support the divisor theory;

nimirum sex primores numeros 1, 2, 3, 4, 5, 6, totidemque his respondentes 10, 12, 15, 20, 30, 60, adeoque omnino duodecim :

without doubt six of them are the first numbers 1, 2, 3, 4, 5, 6, and as many of them are the correspondents 12, 15, 20, 30, 60, precisely entirely twelve;

cum nullus sit numeros eo minor, qui tot admittit;

it is the smallest number which has so many divisors;

nec qui plures admittit ullus qui non hujus saltem duplus sit, (puta 120).

the next number, which has more, is twice as great (that is 120).

Quod de nullo iterim dici poterit, donec ad 360 ventum est, quem fecerunt numerum Graduum in integra Peripheria.

No one can deny that the wind directions are divided into 360 degrees.

Atque hanc divisionem sexagesimalem (in minuta primara, secunda, tertia, caeteraque) praesertim in partibus Arcuum, Angulorum, Temporum, Motuumque coelestium;

And that the division is sexagesimal (in minutes, seconds etc.) -the rest is difficult to translate, but it seems to mean that for instance angular and time measurements (among others?) are sexagesimal quantities-;

retinuerent Arabes (Grecos imitati) et nos post illos etiamnum.

This came to us through the Arabs (imitating the Greek) and stayed with us until even now."

Stevin comes close to the consecutive sequence hypothesis I will postulate in paragraph 4.3. and I talked about 2.1. He recognises also that although calculating in such a big number base is difficult, 60 is chosen because of its many factors.

The Venetian Formaleoni has written a book in Italian from the Enlightenment era, published in 1789 AD, called Dei fonti degli errori nella cosmografia e geographia degli Antichi (English translation of the tittle: About the sources of errors in cosmography and geography from the antiquity.). In this work he more or less postulates an astronomical basis for the sexagesimal system. Here below the original text of relevant passages is given together with an English translation:19,35

"Divisione del circulo in parti sessagesimali; onde nata : suggerita dalla natura : lunghezza dell'anno primitivo. E' singolare la predilezione dell' Antichità per il numero sessagesimale. Il raggio fu diviso in sessanta parti, il gnomone in sessanta segmenti, il giorno in sessanta ore, l’ora in sessanta minuti. Quindi i periodi di sessanta, di cento e ottanta, di seicento, di tremila a seicento, di trentaseimila, introdotti nell’ antica Cronologia, dei quali si trovano la traccie presso i Caldei, i Tatari, gli Egizj, gl’Idiani, e i Cinesi. Si chiederà qual raggione determinar potesse gli antichi osservatori de Cielo a scegliere la divisione sessagesimale a preferenza d’ogn’altra. Questa questione ci conduce a ricerche di molta importanza. Cerchiamo di dilucidare un punto, che nessuno finora ha pensato di porre in chiaro. A little further he continues about this subject: E’ cosa ormai dimostrata, che anticamente l’anno era più breve. Il Sole in trecento sessanta giorni compiva esattamente l’apparente suo corse intorno de Cielo; e per parlare col linguaggio della verità, la terra un tempo non impiegava più di trecento sessanta giornaliere rivoluzione sul suo asse nel percorrere lánnuo suo giro intorno del Sole.

La divisione sessagesimale fu dunque da principio suggerita dalla natura stessa, e dalle prime osservazione."

"The division of the circle in sexagesimal parts; was born: suggested by nature: through the length of the primitive year. This led to a preference in the Antiquity for sexagesimal numbers. The solar ecliptic was divided in parts of sixty, these parts every day a time in sixty segments, the day in sixty hours, The hour in sixty minutes Therefore the periods of sixty, hundred and eighty, six hundred, or multiplication’s of six hundred, of three thousand six hundred, were introduced by ancient chronology, of which traces are found can with the Chaldeans, the Tartars, the Egyptians, the Indians, and the Chinese. But who can we asked to determine why antique observatories of the Sky had a preference for the sexagesimal division? This issue leads us to a search of great importance. We try to elucidate a point, of which nobody, up to now, has shed some light. -A little further he continues about this subject-:

And what is now demonstrated, that the ancient year was to short. It is evident that they observed the race around the Sky of the Sun in exactly three hundred sixty days, in order to speak with the language of the truth, the earth did not employ in their eyes more than three hundred sixty revolutions, every day one covering the year, on its axis in its turn around of the Sun.

The sexagesimal division was therefore, from principle, suggested from the same nature, and the first observations."

Formaleoni comes to this truth from testimonies of ancient authors. And he comes to the above conclusion, which has been taken up again and again in different forms. But why did the Sumerians not divide the circle in to 8 parts of 45, or another whole division of 360? In other words it does not explain why specific 60 was chosen!

Moritz Cantor modifies and deepens the hypothesis of Formaleoni in his first edition (1880 AD) of Vorlesungen ueber Gesichte der Mathematik (I) page 83. Here below only the English translation of the original text is given:19

"The year, which was given the round number of 360 days, gave rise to the circle of 360 degrees, and the division of the circle into six parts, suggested by the fact that the chord of the inscribed hexagon is equal to the radius, gave rise to the number 60, the basis of the system."

Athough this is a sound hypothesis, it emanates from special properties of the number 60. Cantor abandoned it later in favour of the hypothesis of Kewitsch which I will discuss later one.

Lehmann-Haupt, in Zeitschrift fur Assyrologie XIV (1899 AD) page 364, postulates that (only the English translation of the original German text is given):19

"The sexagesimal comes from the fact that in one Babylonian hour (= two of our hours) the sun moves 60 apparent sun diameters (60 Babylonian minutes = 120 of our minutes)."

This implies that the Mesopotamians had a way of measuring the apparent sun diameter. Did they have partly sun blocking lenses of some kind or did they measure it through the clouds?

The next hypothesis in line is that from Zimmer, in "Der egentliche Ursprung des Sexagesimalsystems" Berichte der Philos.-hist. Classe der kgl. Saechs. Ges. Der Wiss. Zu Leipzig. Session of the 14 Nov. 1901 AD. He comes very close to Formaleoni and Cantor. He states in German (given is the original test together with an English translation):19

"In einer von der Vollzahl 360 (= den 360 Tagen des Rundjahres) ausgegangen 6-Teilung (= 60 Tage)."

"Starting from the number 360 (= the 360 days of the solar ecliptic) they did a division by 6 (= 60 days)."

It is actually the same as the Formaleoni hypothesis.

The earlier mentioned Kewitsch points to the fact, in Zeitschrift fur Assyrologie XVII (1904 AD), that neither astronomy nor geometry give the right answer to the question. According to him the sexagismal was a hybrid system invented when two influential people came together. One with a decimal system and one with a base 6 (senary) system, based upon a special mode of numbering the fingers.19

This is highly speculative, since how can one base a senary system on (2 * 5 =) 10 fingers?

Loeffler publishes, in Archiv der Math. Und Physik vol 17 2nd and 3rd Doppelheft (1910 AD) essential the same hypothesis as Theon, Stevin and Wallis, without referring to them.

He says that the sexagesimal system has its origin in the schools of the Sumerian Priests, who recognised the arithmetical properties of 60 as having the first six numbers as its factors.19 This hypothesis comes close to the one about the solely consecutive factors under the breakpoint (√60) I will discuss in paragraph 4.3..

Neugebauer, in a memoir titled Zur Entstehung des Sexagesimalsystems published in 1927 AD, has a new approach. His hypothesis comes from the metrology18 of the Sumerians (given is the original German text19 together with an English translation):19

"Aus dem sexagesimalen Masssystem wird en sexagesimales Zahlensystem."

"A sexagesimal measuring system becomes a sexagesimal number system."

He is essentially right but it shifts the problem. A question remains to be answered: why did the Sumerians initially choose for a sexagesimal measuring system? He has a very interesting answer by saying that an original decimal number system interacting with the process of weighing and measuring led to a sexagesimal number system.26 I will come back about this hypothesis of an original decimal system as I present my own in paragraph 4.3.

Marvin A. Powell Jr. has a unique perspective on the matter. In a publication26 from 1972 AD he postulate a hypothesis with has nothing to do with factorability, astronomy or geometry. His basis of the sexagesimal system comes from an interaction of language and writing. His hypothesis comes down to the fact that there is vigesimal (base 20, originated from counting fingers and toes) aspect in the etymology in the main dialect of the Sumerians and that there is ternary (base 3, unknown origin) aspect in the etymology of another Sumerian dialect. This other dialect is found only in a copy from the Neo-Babylonian period, some 1500 years after the Sumerian language ceased to be widely spoken. The vigesimal and ternary aspect were supposedly combined (20*3 = 60) to the sexagesimal number system.

One thing what undermines this hypothesis is the fact that the etymology of the word niš (= Sumerian for 60) is unknown. It should mean accordingly something like three times twenty, but it does not!

 

4.2. Hypotheses which can be found on the Internet:

And now enough of the outdated stuff, lets see some hypotheses, about the foundation of the sexagesimal number system, from contemporary authors, which can be found on the Internet.

First we have a familiar hypothesis, which we also know from Theon of Alexandria and Formaleoni. This Internet site from an unknown author says: "… for the use of a base sixty counting system is that the number sixty is so rich in factors. This one number has twelve factors alone."27

Secondly I found a new astronomical hypothesis which is based on the sixty years cycle of with the naked eye visible planets Jupiter and Saturn. According to this hypothesis ancient observatories discovered that once in the sixty years there is a conjunction of Jupiter and Saturn on the same place of the zodiac. This gave rise to a mystical status of the number 60 and lead accordingly to the sexagesimal system.28,29

A weak point of this hypothesis is that without a doubt one can find many astronomical phenomena, if one looks for it, which can be expressed by the number 60 or its multiples. Like the much talked about solar ecliptic of 360 (6*60) days. Also think of the 60 days cycle in the Chinese calendar which also must have some kind of astronomical basis.

And finally I found a site with a kind of review article by O’Connor and Robertson about our subject.30 Here two new hypotheses along with some already mentioned are found. I will only discuss here the new ones. The most striking hypothesis was invented by O’Connor and Robertson them self.

As I mentioned at the beginning of this paragraph the decimal and vigesimal number system seems to be chosen for anatomical reasons. O’Connor and Robertson think that this might also be the case for the sexagesimal, if you use the structure of the fingers in the right way. It goes as follows: Take for instance the fingers, except the thumb, of the left hand then you can see three parts separated by the joints for each finger. This gives us a total of twelve parts for four fingers. If you count for each part from one to five on the right hand you can count up to sixty!

A very creative hypothesis indeed, but why did they not count up to 75 including the thumb! In other words why chose the Sumerians base 60 and not base 75? One can also argue; why did they not count up to 300 with the 30 parts of all 10 fingers, and for each part count to 10 on all fingers?

The other "new" one is similar to the hypothesis of Kewitsch, it suggest a hybrid number system was formed when one person with a base 5 number system come together with a person with a base 12 system.

But this just shifts the problem why were a base 5 and base 12 chosen initially?

 

4.3. A new hypothesis about the foundation of the sexagesimal:

This new hypothesis stands on the fact that there was an original decimal system employed by the Sumerians before the early Uruk period (>3500 BC, see Table 4 in paragraph 3.1). Since the decimal system is most obvious for anatomical reasons I suppose the Sumerians used this. There is also an indication found in the scientific literature that a decimal system was used in the region.32 Neugebauer19 for instance also postulates that there was an original metrological decimal system present in Sumer, as I mentioned earlier in paragraph 4.1. Also one can find reminiscences of a decimal system in the metrological sexagesimal systems and in the sexagesimal place notation. Here 10 is used as an intermediate base! (See for instance Fig. 3 and the use of the cuneiform < symbol (< = 10) in Fig. 4 and Table 5.)

Do not make a mistake; most of the hypotheses I talked about in paragraph 4.1. and 4.2., imply, or emerge from the fact that there was original another number system or systems employed in Mesopotamia. Take for instance the first of these hypotheses, the one from Theon of Alexandria. There must have been a number system wherein the resolving of the factors of 60 were calculated.

This decimal system allowed basic arithmetic calculations like resolving in factors of the integers. (In this do not forget; give these ancient people some slack, they were just as intelligent as we are, they only had less science and technology to work with.) An indication of how advanced the mathematics were in this stage is the fact that they already must have found the formula’s xy = [(x+y)2-(x-y)2]/4 and x/y = x*(1/y). How else could they do multiplication’s and divisions in their sexagesimal metrological systems. (See paragraph 3.3.) Resolving in factors and finding the consecutive sequence is just a piece of cake in this regard! With this decimal system they firstly discovered the consecutive sequence. I rediscovered this sequence and talked about it in paragraph 2.1.

It most likely has been the priest caste who did these resolving in factors calculations, since they were in the midst of all economical enterprises. They must have considered the number 60, because of its arithmetical properties, in other words most consecutive factors under √n, as highly mystical. Fact is that the Sumerians coupled their supreme god Anoe to the number 60. They had a pantheon of about 300 gods, but only the gods who where directly under Anoe where also given numbers: 45 (Enlil, god of earth and sky), 30 (Enki, god of the sea) and 15 (Inanna, goddess of love and fertility).31 They therefore chose 60 as a base for there number system and this resulted in the sexagesimal metrological systems and sexagesimal place notation.

What also might have played a role is the fact that because 60 has so much consecutive factors that all of them are easy to remember and thus easy to work with mentally in for instance fractions.

 

5. The Use of Sexagesimal Systems in Other Ancient Cultures

One can find evidence of the use of sexagesimal systems in other ancient cultures like of the Hindu, China and Arabia on the Internet. It seems to be so that in China and in the ancient Hindu cultures this has something to do with the calendar they used.10,33 The Arabians seem to have used a true sexagesimal number system like the Mesopotamians around 1100 AD, beside a decimal system based on Hindu numerals.34

 

-o0o- Please also visit: The new Journal of Randomics site and the cumulated result of the site here

 

Notes & References:

1) Smalley R.E. ‘From balls to tubes to ropes: New materials from carbon’ Presentation for the American Institute of Chemical Engineers South Texas Section, Meeting in Houston, 4 January 1996.

http://cnst.rice.edu/aiche96.html

2) Results not published yet.

3) Illustration from http://www.molecules.com/csc_pg.shtml

4) Anonymous, ‘Base (number)’

http://mathworld.wolfram.com/BaseNumber.html

5) Anonymous, ‘Chapter 3: Hexadecimal and octal notation’

http://www.rz.uni-hohenheim.de/rz/sys/basics/csc102/ch3.html

6) Anonymous, ‘Conversion between binary, octal, and hexadecimal systems’

http://www.redbrick.dcu.ie/help/reference/CLD/AppendixA.doc2.html

7) Anonymous, ‘Sexagesimal or north american system’

http://www.tpub.com/engbas/1-33.htm

8) Melville D.J. ‘Mesopotamian mathematics’ Last modified 15 June 2001

http://it.stlawu.edu/~dmelvill/mesomath/index.html

9) Anonymous ‘About cuneiform writing’ Cuneiform Writing @ University of Pennsylvania Museum of Archaeology and Anthropology

http://www.upenn.edu/museum/Games/cuneiform.html

10) CiYuan L. ‘Traditional chinese astronomical records’

http://www.astro.uni-bonn.de/~pbrosche/iaucomm41/ga2000/as_li.html

11) Anonymous ‘City states (ca 5000 – 2000 BCE)’ The American-Israeli Co-operative Enterprise (2002)

http://www.us-israel.org/jsource/History/citystates.html

12) Lietar B. ‘EXCERPT from: The future of money’ The Origins of Money (1997)

http://www.stim.com/Stim-x/10.1/origins/origins.html

13) Anonymous ‘The world’s first money: Ancient sumerian shell money---Over 5000 years old!’ CollectSource (1998)

http://www.collectsource.com/worlds.htm

14) Its is a matter of discussion if the prime numbers should be considered as having consecutive factors under Ön because by definition they only have one factor in this region, in other words the second factor is above Ön. But the PASCAL program SXGSML8 (see Appendix) includes them in the sequence and so do I.

15) The so-called “even primes” have solely 2 consecutive factors under Ön namely 1 (1*2p) and 2 (2*p). The other two factors above Ön are p and 2p. These numbers are registrated as sequence ID number A001747 in the On-Line Encyclopedia of Integer Sequences:

http://www.research.att.com/~njas/sequences/

15) This sequence is registrated as ID number A066522 at the On-line Encyclopedia of Integer Sequences:

http://www.research.att.com/~njas/sequences/

17) Personal communications, a scientific version of this proof is also given by reference 16.

18) Nissen H.J., Damerow P., Englund R.K. ‘Archaic bookkeeping’ University of Chicago Press (1993)

19) Thureau-Dangin F. ‘Sketch of a history of the sexagesimal system’ Osiris VII 95-99 (1936)

20) Joseph G.G. ‘The crest of the peacock’ page 100, through my reference 21

21) Aldersey-Williams H. ‘The most beautiful molecule’ Aurum Press (1995) Chapter 4, Reference 11, page 307

22) Anonymous ‘Ancient India’s Contribution to Mathematics’

http://india.coolatlanta.com/GreatPages/sudheer/maths.html

23) Anonymous ‘Development of mathematics in ancient china’

http://www.saxakali.com/COLOR_ASP/chinamh1.htm

24) Anonymous ‘Maya mathematics’

http://www.michielb.nl/maya/math.html

25) Anonymous ‘Numbering systems’

http://www.cz3.nus.edu.sg/~dcreamer/cz1105/lec/lec2.pdf

26) Powell Jr. M.A. ‘The Origin of the sexagesimal system: The interaction of language and writing’ Visible Language VI 5-18 (1972)

27) Anonymous ‘The Development of sumerian math’

http://members.aol.com/arbuckled/origin.html

28) Anonymous ‘Basis of the sexagesimal system’

http://www.hssworld.org/hindutva/hindu_calendar/sexagesimal.html

29) Anonymous ‘Proof of the sexagesimal number system’

http://www.hssworld.org/hindutva/hindu_calendar/proof.html

30) O’Connor J.J., Robertson E.F. ‘Babylonian numerals’

http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Babylonian_numerals.html

31) Langen F. ‘7000 Jaar Wereld-geschiedenis: De oorsprong van onze beschaving; Het mesopotamië van de soemeriërs’ Lecturama Rotterdam (1977) page 40-41, In Dutch

32) See 18, page 95

33) Johnson D.W. ‘Exegesis of hindu cosmological time cycles’

http://www.aaronsrod.com/time-cycles/index.html

34) Anonymous ‘The arabic numeral system’

http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Arabic_numerals.html

35) Translated with the help of the Early Modern English Dictionary Database.

http://www.chass.utoronto.ca/english/emed/emedd.html

36) Translated with the help of the program Blitz Latin.

http://www.software-partners.co.uk/blitz_latin.htm