OFFSET
1,1
FORMULA
a(n) ~ 2^n * n^n / (1-exp(-1/2)/2). - Vaclav Kotesovec, Dec 20 2014
MATHEMATICA
Table[Sum[k^(n-k)*(n+k)^k, {k, 0, n}], {n, 1, 20}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, Dec 20 2014
STATUS
approved