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Search: id:A094086
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| A094086 |
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Babylonian reciprocals - factors needed to turn an ugly number into a power of sixty. |
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+0
1
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| 60, 30, 20, 15, 12, 10, 450, 400, 6, 5, 4, 225, 200, 3, 150, 144, 8000, 2, 6750, 100, 90, 80, 75, 72, 4000, 1, 3375, 50, 48, 45, 160000, 40, 2250, 36, 2000, 30, 1728, 101250, 1600, 25, 24, 1350, 80000, 20, 1125, 18, 1000, 16, 15, 3200000, 864, 50625, 800, 750
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Although the Babylonians did not have zero or a decimal point or even a decimal number system, they could calculate fractions, even square and cube roots quite accurately. "30" could mean either thirty or 30/60 = 1/2 or 30/3600 = 1/120 or other such fractions. It would be as if we expressed decimals without zeros or decimal points - 1/2 = 5, 1/4 = 25, 1/8 = 125, 1/10 = 1, etc.
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FORMULA
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a(n) = (60^x)/f(z) where f(z) = A051037 and 60^(x - 1) > n > 60^x
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EXAMPLE
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a(31) = 160000 because the 31st ugly number, f(31) = 81 and (60^4)/81 = 160000
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CROSSREFS
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Cf. A051037.
Sequence in context: A075080 A133000 A033380 this_sequence A112025 A060512 A060513
Adjacent sequences: A094083 A094084 A094085 this_sequence A094087 A094088 A094089
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KEYWORD
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easy,nonn
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AUTHOR
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Michael Joseph Halm (hierogamous(AT)lycos.com), May 01 2004
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