A172401 G.f.: 1/(1-x) = Sum_{n>=0} a(n)*x^n/(1+x)^(2^n-1).

1, 1, 2, 6, 32, 332, 6928, 292334, 24875760, 4254812880, 1459549877168, 1002824206109916, 1379081986798078000, 3794489305535947254732, 20884859614892223147785056, 229923086002576723635638394810

Offset: 0

Author

Paul D. Hanna, Feb 01 2010

Keywords

• nonn

Examples

			1/(1-x) = 1 + x/(1+x) + 2*x^2/(1+x)^3 + 6*x^3/(1+x)^7 + 32*x^4/(1+x)^15 +...
		

Crossrefs

Cf. A172400, A172402, A172403.

Programs

PARI

{a(n)=if(n==0,1,polcoeff(-(1-x)*sum(m=0,n-1,a(m)*x^m/(1+x +x*O(x^n))^(2^m-1)),n))}

Formula

Column 0 of triangle A172400.