OFFSET
0,3
FORMULA
a(n) = n! * Sum_{k=0..floor(n/2)} ((n-2*k+2)/2)^k / (k! * (n-2*k)!).
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(x^2+x*exp(x^2/2))))
(PARI) a(n) = n!*sum(k=0, n\2, ((n-2*k+2)/2)^k/(k!*(n-2*k)!));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Aug 22 2024
STATUS
approved