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1, 1, 3, 7, 22, 81, 331, 1436, 6510, 30129, 141512, 671512, 671538, 3210620, 15443871, 74662005, 362506902
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. [incorrectly gives a(12) = 671512 in Table 4.13]
Björg N. Cyvin, Jon Brunvoll and Sven J. Cyvin, <a href="https://doi.org/10.1007/BFb0018563">Enumeration of benzenoid systems and other polyhexes</a>, p. 65-180 in: I. Gutman (ed.), Advances in the Theory of Benzenoid Hydrocarbons II, Springer, 1992.
a(n) = A018190(n) + A038140(n) + A038141(n). - Andrey Zabolotskiy, Feb 16 2023
a(10)-a(16) from Trinajstić et al. Cyvin, Brunvoll & Cyvin (Table 4.13, the numbers of planar polyhexes with h hexagons1) added by Andrey Zabolotskiy, Feb 08 2023
1, 1, 3, 7, 22, 81, 331, 1436, 6510, 30129, 141512, 671512, 3210620, 15443871, 74662005, 362506902
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.
a(10)-a(16) from Trinajstić et al. (Table 4.13, the numbers of planar polyhexes with h hexagons) added by Andrey Zabolotskiy, Feb 08 2023
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Wenchen He and Wenjie He. "Generation and enumeration of planar polycyclic aromatic hydrocarbons." Tetrahedron 42.19 (1986): 5291-5299. See Table 1.
Wenchen He and Wenjie He, <a href="https://doi.org/10.1016/S0040-4020(01)82078-0">Generation and enumeration of planar polycyclic aromatic hydrocarbons</a>, Tetrahedron 42.19 (1986): 5291-5299. See Table 1.
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A018190 is a very similar sequence with (as He and He remark) a slightly different definition.
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