a(n) = (3*n+6)!!!/6!!!, related to A032031 ((3*n)!!! triple factorials).

A051606

a(n) = (3*n+6)!!!/6!!!, related to A032031 ((3*n)!!! triple factorials).

Terms

    a(0) =1a(1) =9a(2) =108a(3) =1620a(4) =29160a(5) =612360a(6) =14696640a(7) =396809280a(8) =11904278400a(9) =392841187200

External references