%I #10 Jun 23 2020 06:16:13
%S 1,24,5040,3628800,6227020800,20922789888000,121645100408832000,
%T 1124000727777607680000,15511210043330985984000000,
%U 304888344611713860501504000000,8222838654177922817725562880000000
%N a(n) = (3*n+1)!.
%F Sum_{n>=0} 1/a(n) = A143820. - _Amiram Eldar_, Jun 23 2020
%p seq( (3*n+1)!,n=0..13);
%t Table[(3*n+1)!, {n, 0, 10}] (* _Amiram Eldar_, Jun 23 2020 *)
%Y Cf. A000142, A143820.
%K nonn
%O 0,2
%A _Jorge Coveiro_, Dec 26 2004
%E Offset 0 and a(0) added by _Amiram Eldar_, Jun 23 2020