OFFSET
0,2
FORMULA
a(n) ~ 2^(n + 1/2) * n^(2*(n+1)) / exp((4-Pi)*n/2).
MATHEMATICA
Table[Product[n^2+k^2, {k, 0, n}], {n, 0, 15}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, Apr 23 2016
STATUS
approved