a(n) = 24*(3*n + 1)!/(n!*((n + 2)!)^2).

A368875

a(n) = 24*(3*n + 1)!/(n!*((n + 2)!)^2).

Terms

    a(0) =6a(1) =16a(2) =105a(3) =1008a(4) =12012a(5) =164736a(6) =2494206a(7) =40646320a(8) =701149020a(9) =12655450080a(10) =237026033790

External references