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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

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 December 21 23:06 EST 2014. Contains 252326 sequences.