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A303169
a(n) = [x^(n^3)] (1/(1 - x))*(Sum_{k>=0} x^(k^3))^n.
2
1, 2, 6, 30, 241, 2093, 23059, 276056, 3657901, 51751598, 792918670, 13031054778, 228632547574, 4247832219975, 83138970732860, 1710953260292025, 36844216654753387, 827664913984323748, 19363023028132371129, 470436686367280495474, 11843579175327033093769
OFFSET
0,2
COMMENTS
Number of nonnegative solutions to (x_1)^3 + (x_2)^3 + ... + (x_n)^3 <= n^3.
MATHEMATICA
Table[SeriesCoefficient[1/(1 - x) Sum[x^k^3, {k, 0, n}]^n, {x, 0, n^3}], {n, 0, 20}]
CROSSREFS
Main diagonal of A303484.
Sequence in context: A106209 A375226 A003266 * A369198 A097385 A066068
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Apr 19 2018
STATUS
approved