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Search: id:A121220
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| A121220 |
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Number of fixed hexagonal polygons (or benzenoids) with n cells. |
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+0
1
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| 1, 3, 11, 44, 186, 813, 3640, 16590, 76663, 358195, 1688784, 8022273, 38351973, 184353219, 890371070, 4318095442, 21018564402, 102642526470, 502709028125, 2468566918644, 12150769362815, 59937663454017
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OFFSET
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1,2
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REFERENCES
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Markus Voege, Anthony J. Guttmann and Iwan Jensen, "On the number of benzenoid hydrocarbons", J. Chem. Inf. Comput. Sci., (2002), vol. 42, 456-466. See Table 2 under the B_h column on page 462.
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LINKS
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N. J. A. Sloane, Table of n, a(n) for n = 1..46 [from Jensen link]
I. Jensen, First 46 terms
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FORMULA
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See equation 11 on page 463 of the paper by Markus Voege, Anthony J. Guttmann and Iwan Jensen for an asymptotic form for a(n).
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CROSSREFS
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Cf. A018190.
Sequence in context: A091200 A127632 A061706 this_sequence A068091 A001207 A026887
Adjacent sequences: A121217 A121218 A121219 this_sequence A121221 A121222 A121223
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KEYWORD
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nonn
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AUTHOR
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Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Aug 20 2006
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EXTENSIONS
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More terms from njas, Aug 25 2006
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