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A017705 Numerator of sum of -21st powers of divisors of n. 3
1, 2097153, 10460353204, 4398048608257, 476837158203126, 609360030634117, 558545864083284008, 9223376434903384065, 109418989141972712413, 500000238418580150139, 7400249944258160101212, 11501285462682212701357 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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. - Ahmed Fares (ahmedfares(AT)my-deja.com), Apr 05 2001

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

MATHEMATICA

Table[Numerator[DivisorSigma[21, n]/n^21], {n, 1, 20}] (* G. C. Greubel, Nov 05 2018 *)

PROG

(PARI) vector(20, n, numerator(sigma(n, 21)/n^21)) \\ G. C. Greubel, Nov 05 2018

(MAGMA) [Numerator(DivisorSigma(21, n)/n^21): n in [1..20]]; // G. C. Greubel, Nov 05 2018

CROSSREFS

Cf. A017706.

Sequence in context: A017706 A010809 A323659 * A013969 A036099 A253058

Adjacent sequences:  A017702 A017703 A017704 * A017706 A017707 A017708

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified April 9 20:11 EDT 2020. Contains 333362 sequences. (Running on oeis4.)