A298330 - OEIS

A298330

Number of ordered ways of writing n^2 as a sum of n squares of positive integers.

1, 1, 0, 3, 1, 5, 141, 742, 6120, 43888, 300232, 3074478, 28901797, 290411147, 3175037698, 34951274416, 399750066121, 4814421349467, 59532792202344, 768079420764884, 10247011240209066, 140144002390928732, 1978092111496441512, 28633995987157024399

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OFFSET

0,4

LINKS

Table of n, a(n) for n=0..23.

Index entries for sequences related to sums of squares

FORMULA

a(n) = [x^(n^2)] (Sum_{k>=1} x^(k^2))^n.

EXAMPLE

a(3) = 3 because we have [4, 4, 1], [4, 1, 4] and [1, 4, 4].

MATHEMATICA

Table[SeriesCoefficient[(-1 + EllipticTheta[3, 0, x])^n/2^n, {x, 0, n^2}], {n, 0, 23}]

CROSSREFS

Cf. A037444, A066535, A232173, A287617, A298329.

Sequence in context: A370333 A370433 A174424 * A210621 A226771 A096614

Adjacent sequences: A298327 A298328 A298329 * A298331 A298332 A298333

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Jan 17 2018

STATUS

approved