A298938 Number of ordered ways of writing n^3 as a sum of n squares of nonnegative integers.

1, 1, 1, 4, 5, 686, 13942, 455988, 13617853, 454222894, 18323165948, 802161109047, 42149084452070, 2481730049781672, 157265294178424356, 10977302934685469078, 812821237985857557677, 64539935903231450294134, 5504599828399250884049308

Offset

0,4

Links

Table of n, a(n) for n=0..18.

Index entries for sequences related to sums of squares

Formula

a(n) = [x^(n^3)] (Sum_{k>=0} x^(k^2))^n.

Example

a(4) = 5 because we have [64, 0, 0, 0], [16, 16, 16, 16], [0, 64, 0, 0], [0, 0, 64, 0] and [0, 0, 0, 64].

Mathematica

Table[SeriesCoefficient[(1 + EllipticTheta[3, 0, x])^n/2^n, {x, 0, n^3}], {n, 0, 18}]

Crossrefs

Cf. A000290, A000578, A006456, A030273, A037444, A066535, A218494, A232173, A287617, A298329, A298330, A298935, A298936, A298939.

Sequence in context: A042717 A304286 A134463 * A309071 A270975 A058916

Adjacent sequences: A298935 A298936 A298937 * A298939 A298940 A298941

Keyword

nonn

Author

Ilya Gutkovskiy, Jan 29 2018

Status

approved