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A110159
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a(n)=(n+1)(n+2)(n+3)(9n^2+26n+20)/120.
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0
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1, 11, 54, 179, 469, 1050, 2100, 3858, 6633, 10813, 16874, 25389, 37037, 52612, 73032, 99348, 132753, 174591, 226366, 289751, 366597, 458942, 569020, 699270, 852345, 1031121, 1238706, 1478449, 1753949, 2069064, 2427920, 2834920, 3294753
(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 (pp. 167-170, Table 10.5/II/6).
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FORMULA
| G.f.=(1+5x+3x^2)/(1-x)^6.
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MAPLE
| a:=n->(n+1)*(n+2)*(n+3)*(9*n^2+26*n+20)/120: seq(a(n), n=0..35);
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CROSSREFS
| Sequence in context: A172495 A003867 A059135 * A061983 A079884 A200172
Adjacent sequences: A110156 A110157 A110158 * A110160 A110161 A110162
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KEYWORD
| nonn
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AUTHOR
| Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 18 2005
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