A359658 a(n) = Sum_{k=0..n} k^(k * (n-k) + 1).

0, 1, 3, 12, 118, 3345, 337337, 117813304, 182877273548, 1095343802746641, 33833602932485958015, 4588786457956655542361532, 3347980595386754115503487966082, 13023291362471615806961306534915589217

Offset: 0

Author

Seiichi Manyama, Jan 10 2023

Keywords

• nonn

Crossrefs

Cf. A349893, A359659.

Programs

PARI

a(n) = sum(k=0, n, k^(k*(n-k)+1));

PARI

my(N=20, x='x+O('x^N)); concat(0, Vec(sum(k=0, N, k*x^k/(1-k^k*x))))

Formula

G.f.: Sum_{k>=0} k * x^k/(1 - k^k * x).