A377425 E.g.f. satisfies A(x) = 1/(2 - exp(x*A(x)^2))^2.

1, 2, 24, 572, 20788, 1021892, 63498116, 4776128772, 422019084132, 42854861672612, 4918270207805188, 629575456637707076, 88938171122678982692, 13744507646644260776292, 2306659049841490720035780, 417774877069420589127228164, 81222489094387608969950071780

Offset

0,2

Links

Table of n, a(n) for n=0..16.

Formula

E.g.f.: B(x)^2, where B(x) is the e.g.f. of A377424.

a(n) = (2/(4*n+2)!) * Sum_{k=0..n} (4*n+k+1)! * Stirling2(n,k).

Prog

(PARI) a(n) = 2*sum(k=0, n, (4*n+k+1)!*stirling(n, k, 2))/(4*n+2)!;

Crossrefs

Cf. A367134, A376389.

Cf. A377424, A377428.

Sequence in context: A156525 A377490 A377492 * A170904 A090732 A377427

Adjacent sequences: A377422 A377423 A377424 * A377426 A377427 A377428

Keyword

nonn

Author

Seiichi Manyama, Oct 28 2024

Status

approved