|
Search: id:A078469
|
|
|
| A078469 |
|
Number of different compositions of the ladder graph L_n. |
|
+0
2
|
|
| 0, 2, 12, 74, 456, 2810, 17316, 106706, 657552, 4052018, 24969660, 153869978, 948189528, 5843007146, 36006232404, 221880401570, 1367288641824, 8425612252514, 51920962156908, 319951385193962, 1971629273320680
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
REFERENCES
|
J. N. Ridley and M. E. Mays, Compositions of unions of graphs, Fib. Quart. 42 (2004), 222-230.
|
|
LINKS
|
Tanya Khovanova, Recursive Sequences
A. Knopfmacher and M. E. Mays, Graph compositions,Integers 1(2001), #A04.
|
|
FORMULA
|
a(n+2) = 6*a(n-1)+a(n-2). G.f.: 2*x/(1-6*x-x^2).
a(n) = ((3+s)^n-(3-s)^n)/s, where s = sqrt(10).
Asymptotic to (3+sqrt(10))^n/sqrt(10). - Ralf Stephan (ralf(AT)ark.in-berlin.de), Jan 03 2003
|
|
CROSSREFS
|
Adjacent sequences: A078466 A078467 A078468 this_sequence A078470 A078471 A078472
Sequence in context: A037718 A020049 A020004 this_sequence A014351 A074616 A006936
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Ralf Stephan (ralf(AT)ark.in-berlin.de), Jan 02 2003
|
|
|
Search completed in 0.002 seconds
|
