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A162254
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n*(2*n^2 + 5*n + 1)/2.
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6
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4, 19, 51, 106, 190, 309, 469, 676, 936, 1255, 1639, 2094, 2626, 3241, 3945, 4744, 5644, 6651, 7771, 9010, 10374, 11869, 13501, 15276, 17200, 19279, 21519, 23926, 26506, 29265, 32209, 35344, 38676, 42211, 45955, 49914, 54094, 58501, 63141
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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G.f.: x*(4 + 3*x - 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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LinearRecurrence[{4, -6, 4, -1}, {4, 19, 51, 106}, 50] (* or *) CoefficientList[Series[(4+3*x-x^2)/(1-x)^4, {x, 0, 40}], x] (* Vincenzo Librandi, Mar 04 2012 *)
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PROG
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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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EXTENSIONS
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STATUS
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approved
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