OFFSET
0,2
LINKS
Erhan Gürel, On the Occurrence of Perfect Squares Among Values of Certain Polynomial Products, The American Mathematical Monthly 123.6 (2016): 597-599.
FORMULA
a(n) ~ (1 + cosh(Pi)) * 2^(2*n + 2) * n^(4*n + 2) / exp(4*n). - Vaclav Kotesovec, Oct 10 2016
MATHEMATICA
Table[Product[4*k^4+1, {k, 1, n}], {n, 0, 15}] (* Vaclav Kotesovec, Oct 10 2016 *)
PROG
(PARI) a(n) = prod(k=1, n, 4*k^4+1); \\ Michel Marcus, Oct 10 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 20 2016
STATUS
approved