A329805 - OEIS

A329805

Expansion of Product_{i>=1, j>=1} (1 + x^(i*j) + x^(2*i*j)).

1, 1, 3, 4, 10, 14, 27, 39, 71, 101, 170, 242, 390, 551, 852, 1198, 1803, 2512, 3687, 5101, 7351, 10088, 14289, 19472, 27208, 36810, 50790, 68262, 93200, 124453, 168279, 223364, 299473, 395214, 525754, 690103, 911644, 1190447, 1562449, 2030381, 2649162, 3426591

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..41.

FORMULA

G.f.: Product_{k>=1} ((1 - x^(3*k)) / (1 - x^k))^A000005(k).

MATHEMATICA

nmax = 41; CoefficientList[Series[Product[((1 - x^(3 k))/(1 - x^k))^DivisorSigma[0, k], {k, 1, nmax}], {x, 0, nmax}], x]

CROSSREFS

Cf. A000005, A000726, A006171, A107742, A329467.

Sequence in context: A167273 A096380 A309478 * A071019 A173285 A025084

Adjacent sequences: A329802 A329803 A329804 * A329806 A329807 A329808

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Nov 21 2019

STATUS

approved