OFFSET
0,2
MATHEMATICA
Table[Coefficient[Product[(x^k + 1 + 1/x^k)^3, {k, 1, n}], x, 0], {n, 0, 18}]
PROG
(PARI) a(n) = polcoef(prod(k=1, n, (x^k + 1 + 1/x^k)^3), 0); \\ Michel Marcus, Jan 22 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Jan 21 2024
STATUS
approved