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A110695
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Kekule numbers for certain benzenoids of trigonal symmetry.
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0
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1, 9, 341, 14859, 671509, 31816259, 1575219491, 80813149559, 4262996933909, 229858972288659, 12613108252122091, 702092835479959559, 39548041458039952291, 2250117073947022121799, 129122621276859925669799
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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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 313).
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FORMULA
| a(n)=[2binomial(2n, n)-1][binomial(2n, n)^2-binomial(2n, n)+1].
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MAPLE
| a:=n->(2*binomial(2*n, n)-1)*(binomial(2*n, n)^2-binomial(2*n, n)+1); seq(a(n), n=0..16);
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CROSSREFS
| Sequence in context: A090085 A098650 A098652 * A157589 A055601 A203745
Adjacent sequences: A110692 A110693 A110694 * A110696 A110697 A110698
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KEYWORD
| nonn
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AUTHOR
| Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 03 2005
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