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Search: id:A108673
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| A108673 |
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(n+1)(n+2)(n+3)(2n+3)(10n^2+27n+20)/360. |
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+0
1
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| 1, 19, 133, 573, 1848, 4914, 11382, 23766, 45771, 82621, 141427, 231595, 365274, 557844, 828444, 1200540, 1702533, 2368407, 3238417, 4359817, 5787628, 7585446, 9826290, 12593490, 15981615, 20097441, 25060959, 31006423, 38083438, 46458088
(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.231, # 31).
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FORMULA
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G.f.=(1+12z+21z^2+6z^3)/(1-z)^7
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MAPLE
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a:=n->(n+1)*(n+2)*(n+3)*(2*n+3)*(10*n^2+27*n+20)/360: seq(a(n), n=0..32);
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CROSSREFS
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Sequence in context: A142649 A020867 A022679 this_sequence A041692 A078977 A085464
Adjacent sequences: A108670 A108671 A108672 this_sequence A108674 A108675 A108676
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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 17 2005
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