A017712 Denominator of sum of -24th powers of divisors of n.

1, 16777216, 282429536481, 281474976710656, 59604644775390625, 2369190669160808448, 191581231380566414401, 4722366482869645213696, 79766443076872509863361, 500000000000000000000000, 9849732675807611094711841

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..1000

Mathematica

Table[Denominator[DivisorSigma[24, n]/n^24], {n, 1, 20}] (* G. C. Greubel, Nov 03 2018 *)

Prog

(PARI) a(n) = denominator(sigma(n, 24)/n^24); \\ Michel Marcus, Nov 01 2013
(Magma) [Denominator(DivisorSigma(24, n)/n^24): n in [1..20]]; // G. C. Greubel, Nov 03 2018

Crossrefs

Cf. A017711.

Sequence in context: A017624 A016812 A016908 * A010812 A016968 A017040

Adjacent sequences: A017709 A017710 A017711 * A017713 A017714 A017715

Keyword

nonn,frac

Author

N. J. A. Sloane

Status

approved