A369373 a(n) is the constant term in expansion of Product_{k=1..n} (x^k + 1 + 1/x^k)^4.

1, 19, 701, 33873, 1884211, 113091013, 7138569079, 466998324373, 31378587089717, 2152644125539205, 150149036955370989, 10616242785424087153, 759159709650751045807, 54809160248598728775119, 3989668904561505824038609, 292488794939698331845055779, 21576667915867159070829849217

Offset: 0

Author

Ilya Gutkovskiy, Jan 21 2024

Keywords

• nonn

Crossrefs

Cf. A007576, A124996, A156181, A369372.

Programs

Mathematica

Table[Coefficient[Product[(x^k + 1 + 1/x^k)^4, {k, 1, n}], x, 0], {n, 0, 16}]