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A228361
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The number of all possible covers of L-length line segment by 2-length line segments with allowed gaps < 2.
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13
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0, 0, 1, 2, 2, 3, 4, 5, 7, 9, 12, 16, 21, 28, 37, 49, 65, 86, 114, 151, 200, 265, 351, 465, 616, 816, 1081, 1432, 1897, 2513, 3329, 4410, 5842, 7739, 10252, 13581, 17991, 23833, 31572, 41824, 55405, 73396, 97229, 128801, 170625, 226030, 299426, 396655, 525456
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OFFSET
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0,4
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LINKS
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FORMULA
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G.f.: x^2*(1+x)^2/(1-x^2-x^3).
a(n) = a(n-2) +a(n-3) for n >= 5.
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MATHEMATICA
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CoefficientList[Series[(1 - x^2 - x^3)^-1 (1 + x)^2 x^2 , {x, 0, 100}], x]
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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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