A055413 - OEIS

A055413

Number of points in Z^7 of norm <= n.

1, 15, 953, 12435, 88273, 394691, 1405325, 4031123, 10248133, 23120727, 48218513, 93417543, 172039681, 299505299, 503363697, 813950491, 1279144845, 1950568311, 2912136485, 4244109647, 6080556217, 8545686087, 11835454865

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OFFSET

0,2

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..500

FORMULA

a(n) = [x^(n^2)] theta_3(x)^7/(1 - x), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Apr 14 2018

CROSSREFS

Column k=7 of A302997.

Sequence in context: A136419 A231121 A103639 * A067408 A274713 A229840

Adjacent sequences: A055410 A055411 A055412 * A055414 A055415 A055416

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved