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A141354
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Expansion of (1-5*x-x^2+x^3)/((1+x)*(1-x)^3).
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3
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1, -3, -7, -15, -23, -35, -47, -63, -79, -99, -119, -143, -167, -195, -223, -255, -287, -323, -359, -399, -439, -483, -527, -575, -623, -675, -727, -783, -839, -899, -959, -1023, -1087, -1155, -1223, -1295, -1367, -1443, -1519, -1599, -1679, -1763, -1847
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OFFSET
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0,2
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COMMENTS
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Minus A181106 (largest odd number strictly less than a square). [Jerzy Kocik (jkocik(AT)siu.edu), Oct 06 2010]
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LINKS
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FORMULA
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G.f.: (1-5*x-x^2+x^3)/(1-2*x+2*x^3-x^4).
a(n) = 2*a(n-1)-2*a(n-3)+a(n-4), n>3.
a(n) = ((-1)^n-2*n^2-4*n+1)/2. (End)
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MAPLE
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MATHEMATICA
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CoefficientList[Series[(1-5x-x^2+x^3)/((1+x)(1-x)^3), {x, 0, 42}], x] (* Ray Chandler, Dec 05 2011 *)
LinearRecurrence[{2, 0, -2, 1}, {1, -3, -7, -15}, 60] (* Vincenzo Librandi, Sep 10 2015 *)
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PROG
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(Magma) [((-1)^n-2*n^2-4*n+1)/2 : n in [0..100]]; // Wesley Ivan Hurt, Sep 08 2015
(Magma) I:=[1, -3, -7, -15]; [n le 4 select I[n] else 2*Self(n-1)-2*Self(n-3)+Self(n-4): n in [1..50]]; // Vincenzo Librandi, Sep 10 2015
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CROSSREFS
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KEYWORD
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easy,sign
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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