OFFSET
1,3
COMMENTS
In other words, number of 2-sided strip polyhexes with n cells.
REFERENCES
E. M. Palmer, Variations of the cell growth problem, Lect. Notes Math. 303 (1972), 215-224.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
N. Trinajstić, S. Nikolić, J. V. Knop, W. R. Müller and K. Szymanski, Computational Chemical Graph Theory: Characterization, Enumeration, and Generation of Chemical Structures by Computer Methods, Ellis Horwood, 1991.
LINKS
A. T. Balaban, J. Brunvoll, B. N. Cyvin & S. J. Cyvin, Enumeration of branched catacondensed benzenoid hydrocarbons and their numbers of Kekulé structures Tetrahedron, 44(1) (1988), 221-228. See Table 1.
Wenchen He and Wenjie He, Generation and enumeration of planar polycyclic aromatic hydrocarbons, Tetrahedron 42.19 (1986): 5291-5299. See Table 1, column B.
Ed Pegg, Jr., Illustrations of polyforms
Eric Weisstein's World of Mathematics, Polyhex
CROSSREFS
KEYWORD
nonn,more
AUTHOR
EXTENSIONS
a(8)-a(12) from Ed Pegg Jr, May 13 2009
a(13)-a(19) from Joseph Myers, Nov 26 2010
a(20) from Trinajstić et al. (Table 4.2, the number of cata-condensed benzenoids with h hexagons, unbranched) added by Andrey Zabolotskiy, Feb 08 2023
STATUS
approved