A228509 a(n) = binomial(n^2+n+1,n) * (n+1) / (n^2+n+1) for n>=0.

1, 2, 9, 88, 1425, 32886, 992446, 37106784, 1657248417, 86128357150, 5107663394691, 340427678198400, 25194445531808735, 2050156960934135340, 181938723871328671500, 17487609556155439051136, 1809886850192627028383553, 200670984392566362698014110, 23730570474434159458296269953

Offset: 0

Author

Paul D. Hanna, Aug 23 2013

Keywords

• nonn

Examples

			G.f.: A(x) = 1 + 2*x + 9*x^2 + 88*x^3 + 1425*x^4 + 32886*x^5 +...
		

Crossrefs

Cf. A135862, A135860.

Programs

Mathematica

Table[(Binomial[n^2+n+1,n](n+1))/(n^2+n+1),{n,0,20}] (* Harvey P. Dale, Oct 13 2015 *)

PARI

{a(n)=binomial(n^2+n+1,n)*(n+1)/(n^2+n+1)}
for(n=0,20,print1(a(n),", "))

Formula

a(n) = (n+1)*A135862(n).