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A065822
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Numbers k such that 5*phi(k) = 4*sigma(k).
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3
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323, 377, 22591, 42619, 49751, 106711, 119647, 180947, 2782057, 2980823, 2981233, 3794737, 5112427, 5285743, 5732179, 5964229, 6073267, 6669797, 6769927, 7049407, 8025547, 8350633, 8954023, 9373213, 10039471, 10140517, 10842901
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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Select[Range[1085*10^4], 5EulerPhi[#]==4DivisorSigma[1, #]&] (* Harvey P. Dale, Aug 11 2019 *)
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PROG
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(PARI) { n=0; for (m=1, 10^9, if (5*eulerphi(m) == 4*sigma(m), write("b065822.txt", n++, " ", m); if (n==60, return)) ) } \\ Harry J. Smith, Nov 01 2009
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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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