A377717 E.g.f. satisfies A(x) = (1 + (exp(x) - 1) * A(x))^3.

1, 3, 27, 405, 8703, 245493, 8608167, 361640205, 17727268383, 993980112453, 62774530115607, 4410751512076605, 341353603094403663, 28856102576884010613, 2645807719152819131847, 261551674681092859354605, 27732033282190658330940543, 3139533157528775981685527973

Offset: 0

Author

Seiichi Manyama, Nov 04 2024

Keywords

• nonn

Crossrefs

Cf. A000670, A377716.

Cf. A367161, A377693.

Programs

PARI

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

Formula

E.g.f.: B(x)^3, where B(x) is the e.g.f. of A367161.

a(n) = 3 * Sum_{k=0..n} (3*k+2)!/(2*k+3)! * Stirling2(n,k).