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Search: id:A108677
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| A108677 |
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(n+1)(n+2)(n+3)(n+4)(19n^2+47n+30)/720. |
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+0
1
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| 1, 16, 100, 399, 1218, 3108, 6972, 14190, 26763, 47476, 80080, 129493, 202020, 305592, 450024, 647292, 911829, 1260840, 1714636, 2296987, 3035494, 3961980, 5112900, 6529770, 8259615, 10355436, 12876696, 15889825, 19468744, 23695408
(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, # 41).
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FORMULA
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G.f.=(1+9z+9z^2)/(1-z)^7
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MAPLE
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a:=n->(n+1)*(n+2)*(n+3)*(n+4)*(19*n^2+47*n+30)/720: seq(a(n), n=0..33);
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CROSSREFS
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Sequence in context: A014762 A045784 A016958 this_sequence A001249 A014796 A052206
Adjacent sequences: A108674 A108675 A108676 this_sequence A108678 A108679 A108680
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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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