a(n) = binomial((n+1)^2, n) * (2*n+1) / (n+1)^2 for n>=0.

A227469

a(n) = binomial((n+1)^2, n) * (2*n+1) / (n+1)^2 for n>=0.

Terms

    a(0) =1a(1) =3a(2) =20a(3) =245a(4) =4554a(5) =115192a(6) =3709992a(7) =145597545a(8) =6750522350a(9) =361424043596

External references