A132290 Main diagonal of triangle A132289: a(n) = A132289(n,n) for n>=0.

1, 2, 6, 25, 129, 771, 5172, 38280, 308987, 2695586, 25231269, 251869681, 2667876382, 29856632341, 351717286357, 4347357161694, 56222019376378, 758836553993985, 10665452531786380, 155785594704483911

Offset: 0

Author

Paul D. Hanna, Aug 18 2007

Keywords

• nonn

Comments

Equals the binomial transform of A125276.

Crossrefs

Cf. A132289, A125276.

Programs

PARI

{a(n)=local(A=[1]);if(n==0,1,for(i=1,n, A=Vec(Ser(concat(concat(A[ #A],A),A[ #A]))/(1-x)));A[n+1])}

Formula

G.f. A(x) satisfies: A( x*(1-x)/(1+x-x^2) )/(1+x-x^2) = 1 + x*A(x).