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A153793
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13 times pentagonal numbers: a(n) = 13*n*(3*n-1)/2.
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2
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0, 13, 65, 156, 286, 455, 663, 910, 1196, 1521, 1885, 2288, 2730, 3211, 3731, 4290, 4888, 5525, 6201, 6916, 7670, 8463, 9295, 10166, 11076, 12025, 13013, 14040, 15106, 16211, 17355, 18538, 19760, 21021, 22321, 23660, 25038, 26455
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = (39*n^2 - 13*n)/2 = 13*A000326(n).
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>2.
E.g.f.: (13/2)*x*(2+3*x)*exp(x). (End)
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MAPLE
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MATHEMATICA
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Table[13*n*(3*n-1)/2, {n, 0, 25}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 13, 65}, 25] (* G. C. Greubel, Aug 29 2016 *)
13*PolygonalNumber[5, Range[0, 40]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 16 2016 *)
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PROG
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(PARI) a(n) = (39*n^2 - 13*n)/2; \\ Altug Alkan, Aug 29 2016
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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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