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. 231, # 37).
FORMULA
G.f.: (1 + 10*x + 12*x^2 + 2*x^3)/(1-x)^6.
MAPLE
a:=n->(n+1)^2*(n+2)*(5*n^2+15*n+12)/24: seq(a(n), n=0..36);
MATHEMATICA
Table[(n+1)^2(n+2)(5n^2+15n+12)/24, {n, 0, 30}] (* Harvey P. Dale, Apr 10 2022 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Jun 17 2005
STATUS
approved