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Search: id:A017668
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| A017668 |
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Denominator of sum of -2 th powers of divisors of n. |
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+0
2
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| 1, 4, 9, 16, 25, 18, 49, 64, 81, 10, 121, 24, 169, 98, 45, 256, 289, 324, 361, 200, 441, 242, 529, 288, 625, 338, 729, 56, 841, 9, 961, 1024, 1089, 578, 49, 432, 1369, 722, 1521, 160, 1681, 441, 1849, 968, 2025
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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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CROSSREFS
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Cf. A017667.
Adjacent sequences: A017665 A017666 A017667 this_sequence A017669 A017670 A017671
Sequence in context: A070449 A070448 A081403 this_sequence A074373 A067115 A061077
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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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