OFFSET
0,4
FORMULA
a(n) = n! * Sum_{k=0..floor(n/3)} |Stirling1(n-2*k,k)|/(n-3*k+1)!.
PROG
(PARI) a(n) = n!*sum(k=0, n\3, abs(stirling(n-2*k, k, 1))/(n-3*k+1)!);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 11 2024
STATUS
approved