a(n) = 2^n*binomial(2*(n+1), n).

Terms

a(0) =1a(1) =8a(2) =60a(3) =448a(4) =3360a(5) =25344a(6) =192192a(7) =1464320a(8) =11202048a(9) =85995520a(10) =662165504a(11) =5112102912a(12) =39557939200a(13) =306726174720