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Search: id:A110696
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| A110696 |
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Kekule numbers for certain benzenoids of trigonal symmetry. |
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+0
1
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| 1, 28, 1456, 66178, 3014128, 143076778, 7087202890, 363641489638, 19183237689328, 1034361829223578, 56758935931548706, 3159417013205183638, 177966175592478108106, 10125526670502832205398, 581051793331857091649398
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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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
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a(n)=9*binomial(2n, n)^3-15*binomial(2n, n)^2+9*binomial(2n, n)-2.
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MAPLE
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a:=n->9*binomial(2*n, n)^3-15*binomial(2*n, n)^2+9*binomial(2*n, n)-2; seq(a(n), n=0..16);
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CROSSREFS
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Sequence in context: A091993 A118705 A013926 this_sequence A007222 A042515 A042512
Adjacent sequences: A110693 A110694 A110695 this_sequence A110697 A110698 A110699
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KEYWORD
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nonn
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AUTHOR
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Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 03 2005
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