a(n) = Product_{k=0..n-1} (2*n+k-1).

A384261

a(n) = Product_{k=0..n-1} (2*n+k-1).

Terms

    a(0) =1a(1) =1a(2) =12a(3) =210a(4) =5040a(5) =154440a(6) =5765760a(7) =253955520a(8) =12893126400a(9) =741354768000

External references