A137565 Hankel transform of quadruple factorial numbers A001813.

1, 8, 3072, 141557760, 1461147874099200, 5429466527263925207040000, 10652562037579218110269404217344000000, 15215364593060190936848463156185060517032755200000000

Offset: 0

Author

Paul Barry, Jan 26 2008, Apr 25 2008

Keywords

• easy
• nonn

Formula

a(n)=Product{k=0..n-1, (8(k+1)(2k+1))^(n-k)}.

a(n)=8^C(n+1,2)*Product{k=1..n, k!*Product{i=1..k-1, 2i+1}}; a(n)=8^C(n+1,2)*A000178(n)*A057863(n).

Extensions

Edited by N. J. A. Sloane, May 14 2008 at the suggestion of R. J. Mathar.