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A108681
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(n+1)(n+2)^2*(n+3)(n+4)(n+5)(2n+3)/720.
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0
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1, 15, 98, 420, 1386, 3822, 9240, 20196, 40755, 77077, 138138, 236600, 389844, 621180, 961248, 1449624, 2136645, 3085467, 4374370, 6099324, 8376830, 11347050, 15177240, 20065500, 26244855, 33987681, 43610490, 55479088, 70014120
(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.232, # 4).
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FORMULA
| G.f.=(1+z)(1+6z)/(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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CROSSREFS
| Sequence in context: A044266 A044647 A159528 * A108254 A174383 A000973
Adjacent sequences: A108678 A108679 A108680 * A108682 A108683 A108684
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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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