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A067696
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Numbers k such that prime(k) == -1 (mod sigma(k)).
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2
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1, 5, 13, 15, 31, 39, 49, 96, 111, 205, 215, 452, 492, 712, 1258, 5599, 10170, 11514, 32844, 58841, 59550, 83251, 83650, 115139, 120485, 144835, 152583, 467583, 709178, 1617217, 3101711, 3554345, 3714335, 6580179, 8099488
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OFFSET
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1,2
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LINKS
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MATHEMATICA
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Do[s=(Prime[n]+1)/DivisorSigma[1, n]; If[IntegerQ[s], Print[n]], {n, 1000000, 10000000}
Select[Range[81*10^5], Mod[Prime[#]+1, DivisorSigma[1, #]]==0&] (* Harvey P. Dale, May 03 2018 *)
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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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