A377685 E.g.f. satisfies A(x) = (1 - x * log(1 - x*A(x)))^2.

1, 0, 4, 6, 136, 900, 16308, 229320, 4691104, 99156960, 2481162480, 67862678400, 2063842827264, 68473763804160, 2468786906210688, 96048626176339200, 4010912604492410880, 178968539487145282560, 8496991445958129576960, 427734144995749047152640

Offset

0,3

Links

Table of n, a(n) for n=0..19.

Formula

E.g.f.: B(x)^2, where B(x) is the e.g.f. of A371227.

a(n) = 2 * n! * Sum_{k=0..floor(n/2)} (2*n-2*k+1)! * |Stirling1(n-k,k)|/( (n-k)! * (2*n-3*k+2)! ).

Prog

(PARI) a(n) = 2*n!*sum(k=0, n\2, (2*n-2*k+1)!*abs(stirling(n-k, k, 1))/((n-k)!*(2*n-3*k+2)!));

Crossrefs

Cf. A371117, A377686.

Cf. A371227, A377390.

Sequence in context: A375689 A377438 A355232 * A176493 A355230 A070155

Adjacent sequences: A377682 A377683 A377684 * A377686 A377687 A377688

Keyword

nonn

Author

Seiichi Manyama, Nov 04 2024

Status

approved