a(n) = (2n-1)!! * (2n+1)!!, where the double factorial is A006882.

A079484

a(n) = (2n-1)!! * (2n+1)!!, where the double factorial is A006882.

Terms

    a(0) =1a(1) =3a(2) =45a(3) =1575a(4) =99225a(5) =9823275a(6) =1404728325a(7) =273922023375

External references