Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A054880
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A054880 a(n)=3(9^n-1)/4. +0
4
0, 6, 60, 546, 4920, 44286, 398580, 3587226, 32285040, 290565366, 2615088300, 23535794706, 211822152360, 1906399371246, 17157594341220, 154418349070986, 1389765141638880, 12507886274749926 (list; graph; listen)
OFFSET

0,2

COMMENT

Number of walks of length 2n+1 along the edges of a cube between two opposite vertices.

FORMULA

G.f.: (3/4)*1/(1-9*x)-(3/4)/(1-x).

sin(x)^3 = sum k=0, 1, ... (-1)^(k+1) * x^(2k+1)/(2k+1)! * a(k) - Dan Fux (dan.fux(AT)OpenGaia.com or danfux(AT)OpenGaia.com), Apr 08 2001

a(n) = A015518(2n+1)-1 = (A046717(2n+1)-1)/2. - M. F. Hasler, Mar 20 2008

CROSSREFS

{a(n)/6} for n>0 is A002452.

Sequence in context: A102232 A121113 A091710 this_sequence A122653 A136943 A136938

Adjacent sequences: A054877 A054878 A054879 this_sequence A054881 A054882 A054883

KEYWORD

nonn,walk

AUTHOR

Paolo Dominici (pl.dm(AT)libero.it), May 23 2000

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 July 26 13:41 EDT 2008. Contains 142293 sequences.


AT&T Labs Research