OFFSET
0,2
COMMENTS
Kekulé numbers for certain benzenoids.
REFERENCES
S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 229).
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
FORMULA
O.g.f.: (1+11*x+18*x^2+5*x^3)/(-1+x)^8. - R. J. Mathar, Apr 07 2008
MAPLE
a:=n->(1/720)*(n+1)*(n+2)^2*(n+3)*(n+4)*(5*n^2+18*n+15): seq(a(n), n=0..30);
PROG
(Magma) [Floor((1/720)*(n+1)*(n+2)^2*(n+3)*(n+4)*(5*n^2+18*n+15)): n in [0..30]]; // Vincenzo Librandi, Mar 28 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Jun 12 2005
STATUS
approved