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