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

A351501

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

Terms

    a(0) =1a(1) =2a(2) =15a(3) =204a(4) =4095a(5) =109668a(6) =3689595a(7) =149846840a(8) =7141879503a(9) =391139588190

External references