OFFSET
0,4
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)*stirling(j, k, 1)/j!));
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Mar 14 2024
STATUS
approved