Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A026026
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A026026 a(n) = number of (s(0), s(1), ..., s(2n-1)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n, s(0) = 3, s(2n-1) = 4. Also a(n) = T(2n-1,n-1), where T is defined in A026022. +0
2
1, 3, 10, 35, 125, 451, 1638, 5980, 21930, 80750, 298452, 1106921, 4118725, 15371475, 57528750, 215867880, 811985790, 3061229850, 11565545100, 43782423750, 166051490514, 630877833102, 2400830868860, 9150602070760, 34927775872500, 133502608167292 (list; graph; listen)
OFFSET

2,2

FORMULA

Expansion of (1+x^2*C^4)*C^3, where C = (1-(1-4*x)^(1/2))/(2*x) is g.f. for Catalan numbers, A000108.

CROSSREFS

Sequence in context: A112107 A094855 A081567 this_sequence A047037 A134391 A087946

Adjacent sequences: A026023 A026024 A026025 this_sequence A026027 A026028 A026029

KEYWORD

nonn

AUTHOR

Clark Kimberling (ck6(AT)evansville.edu)

EXTENSIONS

Definition corrected by Herbert Kociemba (kociemba(AT)t-online.de), May 02 2004

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


AT&T Labs Research