A375827 E.g.f. satisfies A(x) = exp(x^2 * (exp(x*A(x)) - 1)).

1, 0, 0, 6, 12, 20, 1110, 10122, 58856, 1239912, 23773770, 303367790, 5442263772, 135931189836, 2868815413646, 61708462976370, 1696559552295120, 48121891688969552, 1323641220801211026, 40678367069424137814, 1372011621943725532100

Offset

0,4

Links

Table of n, a(n) for n=0..20.

Formula

a(n) = n! * Sum_{k=0..floor(n/3)} (n-2*k+1)^(k-1) * Stirling2(n-2*k,k)/(n-2*k)!.

Prog

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

Crossrefs

Cf. A030019, A349560.

Cf. A375826.

Sequence in context: A358013 A371116 A356949 * A362892 A371304 A355508

Adjacent sequences: A375824 A375825 A375826 * A375828 A375829 A375830

Keyword

nonn

Author

Seiichi Manyama, Aug 30 2024

Status

approved