OFFSET
0,3
FORMULA
a(n) = n! * Sum_{k=0..floor(n/3)} (-1)^k/(6^k * k!).
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(-x^3/6)/(1-x)))
(PARI) a(n) = n!*sum(k=0, n\3, (-1)^k/(6^k*k!));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Feb 27 2024
STATUS
approved