OFFSET
0,2
LINKS
Daniel Suteu, Table of n, a(n) for n = 0..50
FORMULA
a(n) ~ Pi/4 * A134374(n).
a(n) ~ Pi^2 * 4^(2n + 1) / exp(4n) * n^(4n + 3).
Lim_{n->infinity} a(n) / ((2n+1)!)^2 = Pi/4.
MATHEMATICA
Table[16^n*n*(n!)^4, {n, 0, 12}] (* Wesley Ivan Hurt, Apr 11 2023 *)
PROG
(PARI) a(n) = 16^n * n * (n!)^4;
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Daniel Suteu, Jan 09 2017
STATUS
approved