A356458 Expansion of e.g.f. ( Product_{k>0} B(x^k) )^(1/(1-x)) where B(x) = exp(exp(x)-1) = e.g.f. of Bell numbers.

1, 1, 6, 38, 319, 3117, 36359, 476121, 7025708, 114118746, 2029450055, 39078892305, 810834093733, 17998186069489, 425672049713174, 10676653292086790, 283014906314277059, 7901659174554937925, 231719030698518379003, 7118469816302381503209

Offset: 0

Author

Seiichi Manyama, Aug 08 2022

Keywords

• nonn

Crossrefs

Cf. A356025, A356461.

Cf. A000110, A209903, A355886.

Programs

PARI

my(N=20, x='x+O('x^N)); Vec(serlaplace(prod(k=1, N, exp(exp(x^k)-1))^(1/(1-x))))

PARI

a355886(n) = n!*sum(k=1, n, n\k/k!);
a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, a355886(j)*binomial(i-1, j-1)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} A355886(k) * binomial(n-1,k-1) * a(n-k).