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A015840
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Numbers k such that phi(k) | sigma(k + 3).
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6
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1, 2, 3, 4, 7, 8, 12, 14, 19, 20, 21, 24, 27, 30, 32, 39, 52, 63, 84, 91, 102, 112, 117, 127, 129, 132, 135, 155, 165, 181, 200, 210, 252, 327, 348, 387, 403, 405, 410, 432, 452, 453, 456, 459, 475, 480, 532, 549, 592, 620, 624, 679, 693, 714, 725, 952, 1009
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OFFSET
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1,2
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LINKS
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MAPLE
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MATHEMATICA
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Select[Range[3000], Divisible[DivisorSigma[1, 3 + #], EulerPhi[#]] &] (* David Nacin, Mar 03 2012 *)
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PROG
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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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