A369731 - OEIS

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A369731

Number of solutions to +- 1^3 +- 2^3 +- 3^3 +- ... +- n^3 = 1.

0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 4, 1, 0, 0, 6, 1, 0, 0, 12, 344, 0, 0, 1140, 713, 0, 0, 4384, 5956, 0, 0, 48774, 197767, 0, 0, 1147500, 1097442, 0, 0, 6499466, 11844316, 0, 0, 85185855, 261696060, 0, 0, 1649383741, 2039067290, 0, 0, 13301106607, 25603704324

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OFFSET

0,11

LINKS

Table of n, a(n) for n=0..54.

FORMULA

a(n) = [x^1] Product_{k=1..n} (x^(k^3) + 1/x^(k^3)).

MATHEMATICA

Table[Coefficient[Product[(x^(k^3) + 1/x^(k^3)), {k, 1, n}], x, 1], {n, 0, 50}]

CROSSREFS

Cf. A000578, A063866, A158118, A348892, A350861, A369730, A369732.

Sequence in context: A349354 A354352 A273346 * A136334 A155039 A238858

Adjacent sequences: A369728 A369729 A369730 * A369732 A369733 A369734

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Jan 30 2024

STATUS

approved