OFFSET
0,5
FORMULA
G.f.: Sum_{k>=0} k^k * x^(2*k)/Product_{j=1..k} (1 - j * x).
PROG
(PARI) my(N=40, x='x+O('x^N)); Vec(sum(k=0, N, k^k*x^(2*k)/prod(j=1, k, 1-j*x)))
(PARI) a(n) = sum(k=0, n\2, k^k*stirling(n-k, k, 2));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Apr 09 2022
STATUS
approved