A377577 E.g.f. satisfies A(x) = (1 + x * exp(x) * A(x)^2)^2.

1, 2, 22, 426, 12344, 480010, 23500812, 1389576230, 96382531408, 7675512189714, 690344499939860, 69220070789605582, 7656687699685355256, 926243380308839330426, 121653259759077599227612, 17240419344948437264399670, 2622300119032920100004726432, 426102385668766701871015106338

Offset: 0

Author

Seiichi Manyama, Nov 02 2024

Keywords

• nonn

Crossrefs

Cf. A364987, A377576.

Programs

PARI

a(n) = n!*sum(k=0, n, k^(n-k)*binomial(4*k+2, k)/((2*k+1)*(n-k)!));

Formula

E.g.f.: B(x)^2, where B(x) is the e.g.f. of A364987.

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