OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..25
FORMULA
a(n) = (4n)!^n / A165970(n).
a(n) ~ A^(1/2) * exp(2*n^2 + n - 1/48) / (2^(5*n/2 + 1/6) * Pi^(n/2) * n^(n/2 - 1/24)), where A = A074962 is the Glaisher-Kinkelin constant. - Vaclav Kotesovec, Apr 19 2016
MATHEMATICA
Table[Sqrt[Product[Binomial[4*n, k], {k, 0, 2*n - 1}]], {n, 0, 5}] (* G. C. Greubel, Apr 19 2016 *)
PROG
(PARI) a(n) = sqrtint(prod(k=0, 2*n-1, binomial(4*n, k))); \\ Michel Marcus, Apr 19 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Max Alekseyev, Oct 02 2009
STATUS
approved