A357336 E.g.f. satisfies A(x) = (exp(x) - 1) * exp(3 * A(x)).

0, 1, 7, 100, 2257, 70021, 2768740, 133164109, 7546722487, 492531820066, 36381833190223, 3000677194970137, 273342303933512362, 27256107730344331879, 2952882035628632383975, 345384835617231362018764, 43378466647737203462409829, 5822506028894124326533926193

Offset

0,3

Links

Table of n, a(n) for n=0..17.

Eric Weisstein's World of Mathematics, Lambert W-Function.

Formula

E.g.f.: -LambertW(3 * (1 - exp(x)))/3.

a(n) = Sum_{k=1..n} (3 * k)^(k-1) * Stirling2(n,k).

a(n) ~ sqrt(1 + 3*exp(1)) * n^(n-1) / (3 * exp(n) * log(1 + exp(-1)/3)^(n - 1/2)). - Vaclav Kotesovec, Nov 14 2022

Prog

(PARI) my(N=20, x='x+O('x^N)); concat(0, Vec(serlaplace(-lambertw(3*(1-exp(x)))/3)))
(PARI) a(n) = sum(k=1, n, (3*k)^(k-1)*stirling(n, k, 2));

Crossrefs

Cf. A048802, A357335.

Cf. A349525, A356001.

Sequence in context: A001594 A297151 A052752 * A182529 A322909 A165878

Adjacent sequences: A357333 A357334 A357335 * A357337 A357338 A357339

Keyword

nonn

Author

Seiichi Manyama, Sep 24 2022

Status

approved