

A298330


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


13



1, 1, 0, 3, 1, 5, 141, 742, 6120, 43888, 300232, 3074478, 28901797, 290411147, 3175037698, 34951274416, 399750066121, 4814421349467, 59532792202344, 768079420764884, 10247011240209066, 140144002390928732, 1978092111496441512, 28633995987157024399
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,4


LINKS



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



KEYWORD

nonn


AUTHOR



STATUS

approved



