A352984 a(n) = Sum_{k=0..floor(n/3)} k^(3*n).

1, 0, 0, 1, 1, 1, 262145, 2097153, 16777217, 7625731702716, 205892205836474, 5559069156490116, 4722516577573661689554, 302235507459360068466700, 19342922532827596354169130, 28422947373397605556855075614825, 3552792907042781637051562368414979

Offset

0,7

Links

Seiichi Manyama, Table of n, a(n) for n = 0..185

Formula

G.f.: Sum_{k>=0} (k^3 * x)^(3 * k) / (1 - k^3 * x).

Mathematica

a[0] = 1; a[n_] := Sum[k^(3*n), {k, 0, Floor[n/3]}]; Array[a, 16, 0] (* Amiram Eldar, Apr 13 2022 *)

Prog

(PARI) a(n) = sum(k=0, n\3, k^(3*n));
(PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, (k^3*x)^(3*k)/(1-k^3*x)))

Crossrefs

Cf. A352983.

Sequence in context: A017577 A051441 A351315 * A017699 A013966 A036096

Adjacent sequences: A352981 A352982 A352983 * A352985 A352986 A352987

Keyword

nonn,easy

Author

Seiichi Manyama, Apr 13 2022

Status

approved