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A249354
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a(n) = n*(3*n^2 + 3*n + 1).
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2
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0, 7, 38, 111, 244, 455, 762, 1183, 1736, 2439, 3310, 4367, 5628, 7111, 8834, 10815, 13072, 15623, 18486, 21679, 25220, 29127, 33418, 38111, 43224, 48775, 54782, 61263, 68236, 75719, 83730, 92287, 101408, 111111, 121414, 132335, 143892, 156103, 168986
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OFFSET
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0,2
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COMMENTS
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Also, nonnegative numbers m such that 9*m + 1 is a cube. - Bruno Berselli, May 23 2017
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LINKS
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FORMULA
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G.f.: x*(7+10*x+x^2) / (x-1)^4 . - R. J. Mathar, Oct 28 2014
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MATHEMATICA
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Table[n (3 n^2 + 3 n + 1), {n, 0, 38}] (* or *)
CoefficientList[Series[x (7 + 10 x + x^2)/(x - 1)^4, {x, 0, 38}], x] (* Michael De Vlieger, May 23 2017 *)
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PROG
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CROSSREFS
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Cf. A132355: numbers m such that 9*m + 1 is a square.
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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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