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A002578
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Number of integral points in a certain sequence of open quadrilaterals.
(Formerly M2529 N0997)
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2
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0, 0, 1, 3, 6, 9, 13, 18, 24, 31, 39, 47, 56, 66, 77, 89, 102, 115, 129, 144, 160, 177, 195, 213, 232, 252, 273, 295, 318, 341, 365, 390, 416, 443, 471, 499, 528, 558, 589, 621, 654, 687, 721, 756, 792, 829, 867, 905, 944, 984, 1025, 1067, 1110
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OFFSET
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1,4
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REFERENCES
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Eugene Ehrhart, Deux corollaires de la loi de réciprocité du polyèdre rationnel. C. R. Acad. Sci. Paris Ser. A-B 265, 1967, A160-A162.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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FORMULA
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Ehrhart (1967) gives a g.f. on page 161.
G.f.: x^3*(x^5+x^4+x^2+x+1)/((1-x^6)*(1-x)^2). - Sean A. Irvine, Apr 25 2017
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MATHEMATICA
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CoefficientList[Series[x^2 (1 + x + x^2 + x^4 + x^5) / ((1 - x^6) (1 - x)^2), {x, 0, 40}], x] (* Vincenzo Librandi, Apr 26 2017 *)
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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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EXTENSIONS
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STATUS
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approved
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