A017686 Denominator of sum of -11th powers of divisors of n.

1, 2048, 177147, 4194304, 48828125, 30233088, 1977326743, 8589934592, 31381059609, 50000000000, 285311670611, 185752092672, 1792160394037, 506195646208, 2883251953125, 17592186044416, 34271896307633

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• frac

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

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A017685.

Programs

Magma

[Denominator(DivisorSigma(11,n)/n^11): n in [1..20]]; // G. C. Greubel, Nov 06 2018

Mathematica

Denominator[DivisorSigma[-11,Range[20]]] (* Harvey P. Dale, Dec 18 2012 *)

PARI

vector(20, n, denominator(sigma(n, 11)/n^11)) \\ G. C. Greubel, Nov 06 2018