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

0,3

Links

Table of n, a(n) for n=0..15.

Formula

Column 0 of triangle A172400.

Example

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 +...

Prog

(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))}

Crossrefs

Cf. A172400, A172402, A172403.

Sequence in context: A005736 A354847 A123903 * A272661 A005742 A055612

Adjacent sequences: A172398 A172399 A172400 * A172402 A172403 A172404

Keyword

nonn

Author

Paul D. Hanna, Feb 01 2010

Status

approved