OFFSET
0,2
FORMULA
G.f.: Sum_{k>=0} x^k / (1 - (k+2)*x)^(k+1).
a(n) = Sum_{k=0..n} (k+2)^(n-k) * binomial(n,k).
a(0) = 1; a(n) = 2 * a(n-1) + Sum_{k=1..n} binomial(n-1,k-1) * k * a(n-k). - Ilya Gutkovskiy, Feb 02 2024
PROG
(PARI) a(n) = sum(k=0, n, (k+2)^(n-k)*binomial(n, k));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Dec 03 2023
STATUS
approved