A371159 Expansion of e.g.f. 1/(1 - x^2 - x^3)^x.

1, 0, 0, 6, 24, 60, 1080, 9240, 80640, 1058400, 13759200, 190935360, 3053635200, 51632380800, 941283383040, 18521494992000, 387100672358400, 8613563883724800, 203100697223424000, 5053907407233484800, 132496193336322816000, 3648203578700448768000

Offset

0,4

Links

Table of n, a(n) for n=0..21.

Formula

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

Prog

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

Crossrefs

Cf. A088369, A371160.

Sequence in context: A272951 A358081 A371045 * A371199 A362703 A371046

Adjacent sequences: A371156 A371157 A371158 * A371160 A371161 A371162

Keyword

nonn

Author

Seiichi Manyama, Mar 13 2024

Status

approved