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A108675
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(n+1)(n+2)(61n^4+366n^3+845n^2+888n+360)/720.
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0
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1, 21, 157, 707, 2353, 6405, 15106, 31998, 62349, 113641, 196119, 323401, 513149, 787801, 1175364, 1710268, 2434281, 3397485, 4659313, 6289647, 8369977, 10994621, 14272006, 18326010, 23297365, 29345121, 36648171, 45406837
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Kekule numbers for certain benzenoids.
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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 (p.231, # 35).
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FORMULA
| G.f.=(1+14z+31z^2+14z^3+z^4)/(1-z)^7
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MAPLE
| a:=n->(n+1)*(n+2)*(61*n^4+366*n^3+845*n^2+888*n+360)/720: seq(a(n), n=0..32);
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CROSSREFS
| Sequence in context: A184368 A078396 A180374 * A179097 A070315 A146301
Adjacent sequences: A108672 A108673 A108674 * A108676 A108677 A108678
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KEYWORD
| nonn
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AUTHOR
| Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 17 2005
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