a(n) = binomial(2*n, n - 1)*(2*n + 1)! / n!.

A367776

a(n) = binomial(2*n, n - 1)*(2*n + 1)! / n!.

Terms

    a(0) =0a(1) =6a(2) =240a(3) =12600a(4) =846720a(5) =69854400a(6) =6849722880a(7) =779155977600

External references