a(n) = (2*n+8)!!/8!!, related to A000165 (even double factorials).

A051582

a(n) = (2*n+8)!!/8!!, related to A000165 (even double factorials).

Terms

    a(0) =1a(1) =10a(2) =120a(3) =1680a(4) =26880a(5) =483840a(6) =9676800a(7) =212889600a(8) =5109350400a(9) =132843110400

External references