a(n) = (2n)!! mod (2n-1)!! where k!! = A006882(k).

A232618

a(n) = (2n)!! mod (2n-1)!! where k!! = A006882(k).

Terms

    a(0) =0a(1) =2a(2) =3a(3) =69a(4) =60a(5) =4500a(6) =104580a(7) =186795a(8) =13497435a(9) =442245825a(10) =13003053525a(11) =64585694250

External references