A352841 - OEIS

%I #12 Apr 05 2022 21:20:46

%S 1,1,7,64,851,13906,277972,6466650,172651643,5186830537,173327806752,

%T 6373233407498,255743444526584,11119651415719744,520752884139087852,

%U 26132341317365562754,1398900109763305183707,79569524691656775423766

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

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

%o (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(1-sum(k=1, N, sigma(k, k)*x^k/k!))))

%o (PARI) a(n) = if(n==0, 1, sum(k=1, n, sigma(k, k)*binomial(n, k)*a(n-k)));

%Y Cf. A340903, A340904, A352693.

%Y Cf. A023887, A352839, A352843.

%K nonn

%O 0,3

%A _Seiichi Manyama_, Apr 05 2022