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Search: id:A017670
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| A017670 |
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Denominator of sum of -3 th powers of divisors of n. |
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+0
2
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| 1, 8, 27, 64, 125, 6, 343, 512, 729, 500, 1331, 432, 2197, 343, 375, 4096, 4913, 648, 6859, 4000, 1323, 2662, 12167, 384, 15625, 8788, 19683, 2744, 24389, 125, 29791, 32768, 3993, 19652, 6125, 46656
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OFFSET
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1,2
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COMMENT
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Sum_{d|n} 1/d^k is equal to sigma_k(n)/n^k. So sequences A017665-A017712 also give the numerators and denominators of sigma_k(n)/n^k for k = 1..24. The power sums sigma_k(n) are in sequences A000203 (k=1), A001157-A001160 (k=2,3,4,5), A013954-A013972 for k = 6,7,...,24. - comment from Ahmed Fares (ahmedfares(AT)my-deja.com), Apr 05 2001.
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FORMULA
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Denominator of Sum_{d|n} 1/d^3.
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CROSSREFS
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Cf. A017669.
Adjacent sequences: A017667 A017668 A017669 this_sequence A017671 A017672 A017673
Sequence in context: A141227 A062686 A093322 this_sequence A126200 A076989 A055012
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KEYWORD
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nonn,frac
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AUTHOR
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njas
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