A371231 E.g.f. satisfies A(x) = 1 - x*A(x)^3*log(1 - x*A(x)^3).

1, 0, 2, 3, 152, 930, 42804, 574140, 27267456, 613793376, 31378237200, 1021391030880, 57256014687552, 2456525677525920, 152135168050833408, 8093376365276966400, 554533365688970342400, 35081649646969248529920, 2653840371674014197608448

Offset: 0

Author

Seiichi Manyama, Mar 15 2024

Keywords

• nonn

Crossrefs

Cf. A371121, A371229.

Programs

PARI

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

Formula

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