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A162259
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a(n) = (2*n^3 + 5*n^2 - 17*n)/2.
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1
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-5, 1, 24, 70, 145, 255, 406, 604, 855, 1165, 1540, 1986, 2509, 3115, 3810, 4600, 5491, 6489, 7600, 8830, 10185, 11671, 13294, 15060, 16975, 19045, 21276, 23674, 26245, 28995, 31930, 35056, 38379, 41905, 45640, 49590, 53761, 58159, 62790, 67660
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OFFSET
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1,1
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LINKS
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FORMULA
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Row sums from A155551: a(n) = Sum_{m=1..n} (2*m*n + m + n - 9).
G.f.: x*(-5 + 21*x - 10*x^2)/(1-x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)
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MATHEMATICA
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CoefficientList[Series[(-5+21*x-10*x^2)/(1-x)^4, {x, 0, 40}], x] (* or *) LinearRecurrence[{4, -6, 4, -1}, {-5, 1, 24, 70}, 50] (* Vincenzo Librandi, Mar 04 2012 *)
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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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