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A175109
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a(n) = ((2*n+1)^3+(-1)^n)/2.
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2
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1, 13, 63, 171, 365, 665, 1099, 1687, 2457, 3429, 4631, 6083, 7813, 9841, 12195, 14895, 17969, 21437, 25327, 29659, 34461, 39753, 45563, 51911, 58825, 66325, 74439, 83187, 92597, 102689, 113491, 125023, 137313, 150381, 164255, 178955
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OFFSET
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0,2
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COMMENTS
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Partial sums of A110907. Convolution of the finite sequence (1,10,26,10,1) with A002623.
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LINKS
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FORMULA
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a(n) = 3*a(n-1) -2*a(n-2) -2*a(n-3) +3*a(n-4) -a(n-5).
G.f.: (x^2+4*x+1)*(x^2+6*x+1)/((1+x)*(x-1)^4).
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MAPLE
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MATHEMATICA
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CoefficientList[Series[(x^2 + 4*x + 1)*(x^2 + 6*x + 1)/((1 + x)*(x - 1)^4), {x, 0, 40}], x] (* Vincenzo Librandi, Dec 19 2012 *)
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PROG
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(Magma) I:=[1, 13, 63, 171, 365]; [n le 5 select I[n] else 3*Self(n-1) - 2*Self(n-2) - 2*Self(n-3) + 3*Self(n-4) - Self(n-5): n in [1..40]]; // Vincenzo Librandi, Dec 19 2012
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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