a(n) = A203415(n+1)/A203415(n).

Terms

a(0) =3a(1) =10a(2) =56a(3) =120a(4) =432a(5) =12672a(6) =249600a(7) =873180a(8) =4838400a(9) =296110080a(10) =10786406400a(11) =49621572000a(12) =355053404160