OFFSET
0,2
FORMULA
a(n) ~ 2^n * n^n / (1 - exp(-1)/2). - Vaclav Kotesovec, Dec 26 2023
PROG
(PARI) a(n) = sum(k=0, n, 2^k*k^n);
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Dec 25 2023
STATUS
approved