A185756 Column 1 of triangle A185755.

2, 15, 154, 1995, 31191, 571221, 11992688, 283976517, 7487521975, 217567092743, 6907888374828, 237951469523807, 8838510559556783, 352160268261051113, 14982705940607112640, 677935029521206050505, 32508195354031791206799

Offset

1,1

Comments

Column 0 of triangle A185755 equals n^(n-1).

A185755(n,k) equals the coefficient of x^n*y^k in the n-th iteration of x*(1+xy)/(1-x).

Links

Table of n, a(n) for n=1..17.

Prog

 (PARI) {a(n)=local(A=x, G=x*(1+x*y)/(1-x)); for(i=1, n+1, A=subst(G, x, A+O(x^(n+2)))); polcoeff(polcoeff(A, n+1, x), 1, y)}

Crossrefs

Cf. A185755, A185757, A185758, A185759.

Sequence in context: A191364 A308379 A233832 * A362364 A239107 A124548

Adjacent sequences: A185753 A185754 A185755 * A185757 A185758 A185759

Keyword

nonn

Author

Paul D. Hanna, Feb 03 2011

Status

approved