OFFSET
0,5
FORMULA
a(n) = n! * Sum_{k=0..n} 3^k * k^(n-k) * binomial(1/3,k)/(n-k)!.
PROG
(PARI) a(n) = n!*sum(k=0, n, 3^k*k^(n-k)*binomial(1/3, k)/(n-k)!);
CROSSREFS
KEYWORD
sign,new
AUTHOR
Seiichi Manyama, Jan 12 2025
STATUS
approved