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A123347
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Benzenoids (see the Cyvin-Gutman book for details).
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5
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1, 5, 22, 98, 436, 1940, 8632, 38408, 170896, 760400, 3383392
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Appears to be inverse binomial transform of A138395. If true, then a(n) = ((2+sqrt(6))^(n+1)+(2-sqrt(6))^(n+1))/4, also a(n) = 4*a(n-1)+2*a(n-2) for n > 1 with a(0)=1, a(1)=5, and g.f. is (1+x)/(1-4*x-2*x^2). [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Oct 03 2009]
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REFERENCES
| S. J. Cyvin and I. Gutman, Kekule structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (see p. 78).
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CROSSREFS
| Sequence in context: A200676 A129158 A129164 * A087439 A033452 A179602
Adjacent sequences: A123344 A123345 A123346 * A123348 A123349 A123350
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Oct 10 2006
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