OFFSET
0,4
FORMULA
a(n) = n! * Sum_{k=0..floor(n/2)} (-n+2*k-1)^k/k!.
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(exp(x^2)-x)))
(PARI) a(n) = n!*sum(k=0, n\2, (-n+2*k-1)^k/k!);
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Aug 21 2024
STATUS
approved