A352839 Expansion of g.f. 1/(1 - Sum_{k>=1} sigma_k(k) * x^k).

1, 1, 6, 39, 370, 4132, 59288, 990705, 19577018, 439550259, 11142216938, 313147651821, 9680830606850, 325944181383936, 11875777329091878, 465292113335910106, 19507503314546762246, 871248546067010133794, 41295079536653463057146

Offset

0,3

Links

Table of n, a(n) for n=0..18.

Formula

a(0) = 1; a(n) = Sum_{k=1..n} sigma_k(k) * a(n-k).

Prog

(PARI) my(N=20, x='x+O('x^N)); Vec(1/(1-sum(k=1, N, sigma(k, k)*x^k)))
(PARI) a(n) = if(n==0, 1, sum(k=1, n, sigma(k, k)*a(n-k)));

Crossrefs

Cf. A129921, A180305, A320649.

Cf. A023887, A352841, A352842.

Sequence in context: A356439 A308861 A124577 * A006678 A252761 A145709

Adjacent sequences: A352836 A352837 A352838 * A352840 A352841 A352842

Keyword

nonn

Author

Seiichi Manyama, Apr 05 2022

Status

approved