A359660 a(n) = Sum_{k=0..n} k^(2 * (n-k) + 1).

0, 1, 3, 12, 64, 441, 3855, 41464, 533736, 8071785, 141351715, 2829417276, 64038928728, 1624347614737, 45822087138879, 1427872211276376, 48858282302548240, 1826209988254883889, 74216973833968292451, 3265676709281560408780

Offset

0,3

Links

Table of n, a(n) for n=0..19.

Formula

G.f.: Sum_{k>=0} k * x^k/(1 - k^2 * x).

Prog

(PARI) a(n, s=1, t=2) = sum(k=0, n, k^(t*(n-k)+s));
(PARI) my(N=20, x='x+O('x^N)); concat(0, Vec(sum(k=0, N, k*x^k/(1-k^2*x))))

Crossrefs

Cf. A234568, A349882.

Cf. A000217, A003101.

Sequence in context: A222033 A341769 A302195 * A196559 A111262 A139134

Adjacent sequences: A359657 A359658 A359659 * A359661 A359662 A359663

Keyword

nonn,easy

Author

Seiichi Manyama, Jan 10 2023

Status

approved