A benzenoid is a fusene that is a subgraph of the regular
hexagonal lattice (i.e., a simply connected polyhex).
The numbers of -hexagon
benzenoids for ,
2, ... are 1, 1, 3, 7, 22, 81, 331, 1435, 6505, ... (OEIS A018190;
Brinkmann et al. 2002), which first differs from the counts for fusenes
at .
Brinkmann, G.; Caporossi, G.; and Hansen, P. "A Constructive Enumeration of Fusenes and Benzenoids." J. Algorithms.45, 155-166,
2002.Brinkmann, G.; Caporossi, G.; and Hansen, P. "A Survey and
New Results on Computer Enumeration of Polyhex and Fusene Hydrocarbons." J.
Chem. Inf. Comput. Sci.43, 842-851, 2003.Sloane, N. J. A.
Sequence A018190 in "The On-Line Encyclopedia
of Integer Sequences."
-hexagon
benzenoids for 
,
2, ... are 1, 1, 3, 7, 22, 81, 331, 1435, 6505, ... (OEIS A018190;
Brinkmann et al. 2002), which first differs from the counts for fusenes
at 
.
