%I #9 Jul 10 2020 00:00:26
%S 1,21,1025310,393143628567690,4161601591128480023923529880,
%T 3025979870886810157320547152897281546399520600,
%U 316069513961213168272637175554794298273860325049869267706740636689200
%N a(n) = (n-1)! * Product_{i=1..n-1} ((2*n)!-2*i-1).
%D Barry Simon, Representations of Finite and Compact Groups, AMS, p. 233.
%t Table[(n - 1)!*Product[(2 n)! - 2 i - 1, {i, n - 1}], {n, 7}] (* _Wesley Ivan Hurt_, May 07 2014 *)
%K nonn,easy
%O 1,2
%A _N. J. A. Sloane_, Dec 11 1999