Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #7 Oct 26 2017 16:13:17
%S 6,30240,435891456000,64630041847212441600000,
%T 258328699159653623241666283438080000000
%N a(n) = (n^2)!/(2*(n!)).
%F a(n) ~ n^(2*n^2 - n + 1/2) / (2 * exp(n*(n-1))). - _Vaclav Kotesovec_, Oct 26 2017
%t Table[(n^2)!/(2(n!)), {n, 2, 6}]
%Y Cf. A000142, A001044, A000442, A036740, A010050, A009445, A134366, A134367, A134368, A134369, A134371, A134372, A134373, A134374, A134374
%K nonn
%O 2,1
%A _Artur Jasinski_, Jan 16 2007