OFFSET
0,4
FORMULA
a(n) = [x^1] Product_{k=1..2*n-1} (x^(2*k-1) + 1/x^(2*k-1)).
MATHEMATICA
Table[Coefficient[Product[(x^(2 k - 1) + 1/x^(2 k - 1)), {k, 1, 2 n - 1}], x, 1], {n, 0, 27}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Jan 30 2024
STATUS
approved