OFFSET
0,3
FORMULA
a(n) = Sum_{k=0..floor(n/2)} (n-k)^(k*(n-k)) * binomial(n-k,k).
PROG
(PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, (x*(1+k^k*x))^k))
(PARI) a(n) = sum(k=0, n\2, (n-k)^(k*(n-k))*binomial(n-k, k));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Feb 16 2023
STATUS
approved