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Search: id:A107916
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| A107916 |
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(1/12)binomial(n+3,2)*binomial(n+4,3)*binomial(n+5,5). |
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+0
1
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| 1, 30, 350, 2450, 12348, 49392, 166320, 490050, 1297725, 3149146, 7105098, 15071420, 30321200, 58262400, 107535744, 191548044, 330569505, 554550150, 906840550, 1449035742, 2267198780, 3479762000, 5247450000, 7785618750
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Kekule numbers for certain benzenoids.
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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 (p. 229).
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FORMULA
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a(n)=(1/17280)(n+1)(n+2)^3*(n+3)^3*(n+4)^2*(n+5)
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MAPLE
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a:=n->(1/12)*binomial(n+3, 2)*binomial(n+4, 3)*binomial(n+5, 5): seq(a(n), n=0..30);
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CROSSREFS
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Sequence in context: A107967 A115500 A125418 this_sequence A091775 A008656 A086864
Adjacent sequences: A107913 A107914 A107915 this_sequence A107917 A107918 A107919
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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), Jun 12 2005
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