a(n) = Product_{k = 1..n-1} (9*k - 2).

A147631

a(n) = Product_{k = 1..n-1} (9*k - 2).

Terms

    a(0) =1a(1) =7a(2) =112a(3) =2800a(4) =95200a(5) =4093600a(6) =212867200a(7) =12984899200a(8) =908942944000

External references