A377541 E.g.f. satisfies A(x) = 1/(1 - x * exp(x*A(x)))^2.

1, 2, 10, 90, 1184, 20650, 450252, 11803526, 361892848, 12712357170, 503564718260, 22212233618542, 1079909444635848, 57379354040049002, 3308238701451609772, 205715613407117613270, 13724187813695296374752, 977841609869801208944482, 74108335568947966714172004

Offset

0,2

Links

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

Formula

E.g.f.: B(x)^2, where B(x) is the e.g.f. of A364980.

a(n) = 2 * n! * Sum_{k=0..n} k^(n-k) * binomial(2*n-k+2,k)/( (2*n-k+2)*(n-k)! ).

Prog

(PARI) a(n) = 2*n!*sum(k=0, n, k^(n-k)*binomial(2*n-k+2, k)/((2*n-k+2)*(n-k)!));

Crossrefs

Cf. A161633, A377545, A377551.

Cf. A364980.

Sequence in context: A366268 A198434 A326089 * A277403 A179423 A320962

Adjacent sequences: A377538 A377539 A377540 * A377542 A377543 A377544

Keyword

nonn

Author

Seiichi Manyama, Oct 31 2024

Status

approved