A371304 E.g.f. satisfies A(x) = 1/(1 - x^2*(exp(x*A(x)) - 1)).

1, 0, 0, 6, 12, 20, 1470, 12642, 70616, 2131992, 39352410, 470186750, 11032124532, 295053244356, 5896487364950, 146264289411450, 4625791393554480, 130492119237611312, 3837833086814864946, 135471306780659593206, 4800394977109827314060

Offset

0,4

Links

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

Formula

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

Prog

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

Crossrefs

Cf. A370989, A371139.

Cf. A358013, A371302.

Sequence in context: A356949 A375827 A362892 * A355508 A371139 A371145

Adjacent sequences: A371301 A371302 A371303 * A371305 A371306 A371307

Keyword

nonn

Author

Seiichi Manyama, Mar 18 2024

Status

approved