OFFSET
0,3
FORMULA
E.g.f.: Sum_{k>=0} (k * x)^(2 * k) / (k! * (1 - k * x)).
PROG
(PARI) a(n) = n!*sum(k=0, n\2, k^n/k!);
(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(sum(k=0, N, (k*x)^(2*k)/(k!*(1-k*x)))))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 17 2022
STATUS
approved