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A017694 Denominator of sum of -15th powers of divisors of n. 3
1, 32768, 14348907, 1073741824, 30517578125, 13060694016, 4747561509943, 35184372088832, 205891132094649, 500000000000000, 4177248169415651, 3851755393646592, 51185893014090757, 19446011944726528, 48654876708984375 (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[Denominator[DivisorSigma[15, n]/n^15], {n, 1, 20}] (* G. C. Greubel, Nov 05 2018 *)

PROG

(PARI) vector(20, n, denominator(sigma(n, 15)/n^15)) \\ G. C. Greubel, Nov 05 2018

(MAGMA) [Denominator(DivisorSigma(15, n)/n^15): n in [1..20]]; // G. C. Greubel, Nov 05 2018

CROSSREFS

Cf. A017693.

Sequence in context: A017489 A017621 A195251 * A010803 A236223 A183817

Adjacent sequences:  A017691 A017692 A017693 * A017695 A017696 A017697

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified April 6 21:24 EDT 2020. Contains 333286 sequences. (Running on oeis4.)