A384895 G.f. A(x) satisfies A(x) = 1 + x/A(-x*A(x)^2)^2.

1, 1, 2, 3, 4, -3, -50, -237, -872, -2375, -3522, 11383, 140170, 830999, 3797676, 13901117, 36231696, 12991001, -656219096, -5809148691, -35189341480, -173155983991, -699938697650, -2079618264082, -1460269315332, 39890883936437, 413233629798312, 2857552649413347

Offset: 0

Author

Seiichi Manyama, Jun 12 2025

Keywords

• sign

Crossrefs

Column k=1 of A384900.

Cf. A000108, A213094, A213095, A384894.

Programs

PARI

a(n, k=-1) = if(n*k==0, 0^n, (-1)^n*k*sum(j=1, n, binomial(-2*n+3*j+k-1, j-1)*a(n-j, 2*j)/j));

Formula

See A384900.