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A239592
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a(n) = (n^4 - n^3 + 4*n^2 + 2)/2.
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2
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1, 3, 13, 46, 129, 301, 613, 1128, 1921, 3079, 4701, 6898, 9793, 13521, 18229, 24076, 31233, 39883, 50221, 62454, 76801, 93493, 112773, 134896, 160129, 188751, 221053, 257338, 297921, 343129, 393301, 448788, 509953, 577171, 650829, 731326, 819073, 914493
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OFFSET
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0,2
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COMMENTS
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Main diagonal of square array A239331.
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LINKS
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FORMULA
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G.f.: (1 - 2*x + 8*x^2 + x^3 + 4*x^4)/(1-x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5), a(0) = 1, a(1) = 3, a(2) = 13, a(3) = 46, a(4) = 129.
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MATHEMATICA
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CoefficientList[Series[(1 - 2 x + 8 x^2 + x^3 + 4 x^4)/(1 - x)^5, {x, 0, 40}], x] (* Vincenzo Librandi, Mar 23 2014 *)
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PROG
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(PARI) Vec((1-2*x+8*x^2+x^3+4*x^4)/(1-x)^5 + O(x^100)) \\ Colin Barker, Mar 22 2014
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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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