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Search: id:A108684
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| A108684 |
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(n+1)(n+2)(n+3)(19n^3+111n^2+200n+120)/720. |
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+0
1
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| 1, 15, 93, 372, 1141, 2926, 6594, 13476, 25509, 45397, 76791, 124488, 194649, 295036, 435268, 627096, 884697, 1224987, 1667953, 2237004, 2959341, 3866346, 4993990, 6383260, 8080605, 10138401, 12615435, 15577408, 19097457, 23256696
(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.233, # 10).
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FORMULA
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G.f.=(1+8z+9z^2+z^3)/(1-z)^7
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MAPLE
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a:=n->(n+1)*(n+2)*(n+3)*(19*n^3+111*n^2+200*n+120)/720: seq(a(n), n=0..33);
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CROSSREFS
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Sequence in context: A020255 A041428 A052226 this_sequence A125325 A126483 A114240
Adjacent sequences: A108681 A108682 A108683 this_sequence A108685 A108686 A108687
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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 19 2005
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