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A317973
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a(n) = 2*(a(n-1)+a(n-2)+a(n-3))-a(n-4) for n >= 4, with initial terms -1, 2, 3, 6.
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4
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-1, 2, 3, 6, 23, 62, 179, 522, 1503, 4346, 12563, 36302, 104919, 303222, 876323, 2532626, 7319423, 21153522, 61134819, 176682902, 510623063, 1475728046, 4264933203, 12325885722, 35622470879, 102950851562, 297533483123, 859887725406, 2485121649303, 7182134864102
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f.: (-1 + 4*x + x^2 - 2*x^3)/(1 - 2*x - 2*x^2 - 2*x^3 + x^4). - Andrew Howroyd, Sep 08 2018
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MATHEMATICA
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PROG
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(PARI) Vec((-1 + 4*x + x^2 - 2*x^3)/(1 - 2*x - 2*x^2 - 2*x^3 + x^4) + O(x^40)) \\ Andrew Howroyd, Sep 08 2018
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CROSSREFS
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KEYWORD
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sign,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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