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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
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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; 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, # 10).
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FORMULA
| G.f.=(1+8z+9z^2+z^3)/(1-z)^7
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MAPLE
| 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
| Sequence in context: A180248 A041428 A052226 * A125325 A126483 A114240
Adjacent sequences: A108681 A108682 A108683 * A108685 A108686 A108687
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KEYWORD
| nonn
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AUTHOR
| Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 19 2005
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