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A171621
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Numerator of 1/4 - 1/n^2, each fourth term multiplied by 4.
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6
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0, 5, 3, 21, 8, 45, 15, 77, 24, 117, 35, 165, 48, 221, 63, 285, 80, 357, 99, 437, 120, 525, 143, 621, 168, 725, 195, 837, 224, 957, 255, 1085, 288, 1221, 323, 1365, 360, 1517, 399, 1677, 440, 1845, 483, 2021, 528
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OFFSET
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2,2
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COMMENTS
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These are the square roots of the fifth column of the array of denominators mentioned in A171522.
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LINKS
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FORMULA
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G.f.: x^3*(-5-3*x-6*x^2+x^3+3*x^4) / ( (x-1)^3*(1+x)^3 ). - R. J. Mathar, Apr 02 2011
a(n) = -(-5+3*(-1)^n)*(-4+n^2)/8. - Colin Barker, Nov 03 2014
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MAPLE
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A061037 := proc(n) 1/4-1/n^2 ; numer(%) ; end proc:
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MATHEMATICA
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Table[-(-5+3*(-1)^n)*(-4+n^2)/8, {n, 0, 100}] (* G. C. Greubel, Sep 19 2018 *)
LinearRecurrence[{0, 3, 0, -3, 0, 1}, {0, 5, 3, 21, 8, 45}, 50] (* Harvey P. Dale, Nov 01 2019 *)
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PROG
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(PARI) concat(0, Vec(x^3*(-5-3*x-6*x^2+x^3+3*x^4)/((x-1)^3*(1+x)^3) + O(x^100))) \\ Colin Barker, Nov 03 2014
(Magma) [-(-5+3*(-1)^n)*(-4+n^2)/8: n in [0..100]]; // G. C. Greubel, Sep 19 2018
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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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