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A017671
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Numerator of sum of -4 th powers of divisors of n.
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2
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1, 17, 82, 273, 626, 697, 2402, 4369, 6643, 5321, 14642, 3731, 28562, 20417, 51332, 69905, 83522, 112931, 130322, 85449, 196964, 124457, 279842, 179129, 391251, 242777, 538084, 46839, 707282, 218161, 923522, 1118481, 1200644, 41761, 1503652, 604513, 1874162
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OFFSET
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1,2
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COMMENTS
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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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LINKS
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Table of n, a(n) for n=1..37.
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MATHEMATICA
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A017671[n_Integer] := Numerator[DivisorSigma[-4, n]]; A017671 /@ Range[100] (* From Vladimir Joseph Stephan Orlovsky, Jul 21 2011 *)
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CROSSREFS
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Cf. A017672.
Sequence in context: A088687 A034678 A065960 * A001159 A053820 A142059
Adjacent sequences: A017668 A017669 A017670 * A017672 A017673 A017674
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KEYWORD
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nonn,frac
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AUTHOR
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N. J. A. Sloane.
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STATUS
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approved
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