login
This site is supported by donations to The OEIS Foundation.

 

Logo

Many excellent designs for a new banner were submitted. We will use the best of them in rotation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A172401 G.f.: 1/(1-x) = Sum_{n>=0} a(n)*x^n/(1+x)^(2^n-1). 3
1, 1, 2, 6, 32, 332, 6928, 292334, 24875760, 4254812880, 1459549877168, 1002824206109916, 1379081986798078000, 3794489305535947254732, 20884859614892223147785056, 229923086002576723635638394810 (list; graph; refs; listen; history; text; internal format)
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: A191712 A005736 A123903 * A005742 A055612 A236691

Adjacent sequences:  A172398 A172399 A172400 * A172402 A172403 A172404

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Feb 01 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified April 20 16:29 EDT 2014. Contains 240807 sequences.