|
Search: id:A109111
|
|
|
| A109111 |
|
(1/sqrt(595))((sqrt(595)+26)(125+5sqrt(595))^n+(sqrt(595)-26)(125-5sqrt(595))^n). |
|
+0
1
|
|
| 2, 510, 126000, 31117500, 7684875000, 1897880625000, 468706500000000, 115753214531250000, 28586773757812500000, 7059878528554687500000, 1743529551820312500000000, 430587479058662109375000000
(list; graph; listen)
|
|
|
OFFSET
|
0,1
|
|
|
COMMENT
|
Kekule numbers for certain benzenoids.
|
|
REFERENCES
|
S. J. Cyvin and I. Gutman, Kekule structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p.292).
|
|
FORMULA
|
G.f.=2(1+5z)/(1-250z+750z^2).
|
|
MAPLE
|
a:=n->(1/sqrt(595))*((sqrt(595)+26)*(125+5*sqrt(595))^n+(sqrt(595)-26)*(125-5*sq\ rt(595))^n): seq(expand(a(n)), n=0..13);
|
|
CROSSREFS
|
Adjacent sequences: A109108 A109109 A109110 this_sequence A109112 A109113 A109114
Sequence in context: A027655 A024032 A109032 this_sequence A004886 A139302 A003391
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 19 2005
|
|
|
Search completed in 0.002 seconds
|
