OFFSET
1,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..167
FORMULA
Logarithmic derivative of A174471.
G.f.: Sum_{k>=1} k^sigma(k) * x^k/(1 - x^k). - Seiichi Manyama, Oct 14 2021
MATHEMATICA
a[n_] := DivisorSum[n, #^DivisorSigma[1, #] &]; Array[a, 16] (* Amiram Eldar, Oct 08 2021 *)
PROG
(PARI) {a(n)=sumdiv(n, d, d^sigma(d))}
(PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=1, N, k^sigma(k)*x^k/(1-x^k))) \\ Seiichi Manyama, Oct 14 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Apr 04 2010
STATUS
approved