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A108676
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a(n) = (n+1)^2*(n+2)*(5*n^2 + 15*n + 12)/24.
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0
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1, 16, 93, 340, 950, 2226, 4606, 8688, 15255, 25300, 40051, 60996, 89908, 128870, 180300, 246976, 332061, 439128, 572185, 735700, 934626, 1174426, 1461098, 1801200, 2201875, 2670876, 3216591, 3848068, 4575040, 5407950, 6357976
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OFFSET
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0,2
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COMMENTS
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Kekulé numbers for certain benzenoids.
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REFERENCES
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S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 231, # 37).
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LINKS
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FORMULA
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G.f.: (1 + 10*x + 12*x^2 + 2*x^3)/(1-x)^6.
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MAPLE
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a:=n->(n+1)^2*(n+2)*(5*n^2+15*n+12)/24: seq(a(n), n=0..36);
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MATHEMATICA
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Table[(n+1)^2(n+2)(5n^2+15n+12)/24, {n, 0, 30}] (* Harvey P. Dale, Apr 10 2022 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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