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A180415
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a(n) = (n^3 - 3n^2 + 14n - 6)/6.
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2
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1, 3, 6, 11, 19, 31, 48, 71, 101, 139, 186, 243, 311, 391, 484, 591, 713, 851, 1006, 1179, 1371, 1583, 1816, 2071, 2349, 2651, 2978, 3331, 3711, 4119, 4556, 5023, 5521, 6051, 6614, 7211, 7843, 8511, 9216, 9959, 10741, 11563, 12426, 13331, 14279, 15271, 16308
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OFFSET
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1,2
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COMMENTS
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Binomial transform of 0,1,1,0,bar(1,-1), where bar(..) denotes a periodically repeated sequence.
If the offset is set to 0, this is the binomial transform of the quasi-finite sequence 1,2,1,1,bar(0).
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LINKS
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FORMULA
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G.f. x*(x^3 - x + 1)/(x-1)^4.
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EXAMPLE
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Representation as binomial transform: a(4) = 11 = (1, 2, 1, 1) dot (1, 3, 3, 1) = (1 + 6 + 3 + 1).
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MATHEMATICA
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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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Sequence extended, nomenclature of variables normalized, g.f. multiplied by x, binomial transforms clarified - R. J. Mathar, Sep 04 2010
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STATUS
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approved
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