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