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A108682
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(n+1)(n+2)^2*(n+3)(n+4)(4n^2+15n+15)/720.
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0
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1, 17, 122, 560, 1946, 5586, 13944, 31284, 64515, 124267, 226226, 392756, 654836, 1054340, 1646688, 2503896, 3718053, 5405253, 7710010, 10810184, 14922446, 20308310, 27280760, 36211500, 47538855, 61776351, 79522002, 101468332
(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.233, # 7).
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FORMULA
| G.f.=(1+9z+14z^2+4z^3)/(1-z)^8
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MAPLE
| G:=factor(sum(a(n)*z^n, n=0..infinity)); series(G, z=0, 37);
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MATHEMATICA
| Table[(n+1)(n+2)^2(n+3)(n+4)(4n^2+15n+15)/720, {n, 0, 40}] (* or *)
CoefficientList[Series[(1+9x+14x^2+4x^3)/(1-x)^8, {x, 0, 40}], x] (* From Harvey P. Dale, Mar 28 2011 *)
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CROSSREFS
| Sequence in context: A022709 A196806 A094944 * A031213 A196145 A021003
Adjacent sequences: A108679 A108680 A108681 * A108683 A108684 A108685
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KEYWORD
| nonn
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AUTHOR
| Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 18 2005
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