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A069166
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Numbers k such that k*Sum_{d|k} 1/sigma(d) is an integer.
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1
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1, 6, 14, 40, 120, 244, 280, 440, 494, 680, 920, 1220, 2040, 2840, 2968, 3480, 6360, 9880, 10680, 16376, 20618, 25160, 32280, 34720, 40136, 40280, 42136, 45560, 45994, 46280, 85880, 91160, 120408, 200680, 213280, 231080, 242840, 377080, 410552, 412360, 421480, 441496, 447320
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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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Select[Range[125000], IntegerQ[# Total[1/DivisorSigma[1, Divisors[#]]]]&] (* Harvey P. Dale, Nov 03 2017 *)
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PROG
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(PARI) isok(k) = denominator(k*sumdiv(k, d, 1/sigma(d))) == 1; \\ Michel Marcus, Feb 15 2021
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CROSSREFS
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KEYWORD
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easy,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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