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A114070
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sigma(n) + n is a cube.
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0
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13, 76, 280, 4258, 4719, 4887, 12207, 13106, 41823, 42804, 51671, 54261, 56283, 65512, 77671, 95139, 98219, 135724, 147440, 149176, 177911, 220546, 239599, 279145, 285347, 285957, 299432, 308503, 312137, 335106, 350739, 525429, 611123, 634600, 663377, 700064
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OFFSET
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1,1
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LINKS
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EXAMPLE
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sigma(13) + 13 = 27 = 3^3.
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MATHEMATICA
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Select[Range[701100], IntegerQ[Surd[DivisorSigma[1, #]+#, 3]]&] (* Harvey P. Dale, Oct 22 2023 *)
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PROG
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(PARI) isok(n) = ispower(sigma(n) + n, 3); \\ Michel Marcus, Jan 22 2014
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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