a(n) = 3*((2*n+2)!)^2 / (n!*(n+1)!*(n+2)!*(n+3)!).
A227169
a(n) = 3*((2*n+2)!)^2 / (n!*(n+1)!*(n+2)!*(n+3)!).
Terms
- a(0) =1a(1) =6a(2) =45a(3) =392a(4) =3780a(5) =39204a(6) =429429a(7) =4907760a(8) =58023108a(9) =705264040a(10) =8772399636a(11) =111263122656
External references
- oeis: A227169