A382950 a(n) = [(x*y)^n] Product_{k>=1} (1 + x^k + y^k)^n.

1, 0, 6, 102, 1342, 20030, 306852, 4783534, 75873934, 1220259306, 19837742836, 325375411438, 5376744428812, 89412908941096, 1494992390431000, 25114561595879252, 423649216254936110, 7172523302899053230, 121828099966104173892, 2075321708914763792740

Offset

0,3

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..200

Formula

a(n) ~ c * d^n / n, where d = 17.95370167248385600263... and c = 0.0600668009236121058... - Vaclav Kotesovec, Apr 10 2025

Mathematica

Table[SeriesCoefficient[Product[(1 + x^k + y^k)^n, {k, 1, n}], {x, 0, n}, {y, 0, n}], {n, 0, 19}]

Crossrefs

Cf. A270913, A365662.

Sequence in context: A344400 A277662 A371250 * A022025 A302911 A174481

Adjacent sequences: A382947 A382948 A382949 * A382951 A382952 A382953

Keyword

nonn

Author

Ilya Gutkovskiy, Apr 09 2025

Status

approved