OFFSET
0,3
FORMULA
a(n) = Sum_{k=0..n} (1 + 2*(n - k))*k^(n-k).
MATHEMATICA
Join[{1}, Table[Sum[(1+2(n-k))k^(n-k), {k, 0, n}], {n, 25}]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Stefano Spezia, May 08 2023
STATUS
approved