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A074891
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Numbers n such that sigma(n) = phi(3n).
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3
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15, 35, 357, 1045, 3339, 5049, 10659, 12441, 24871, 24969, 29029, 50065, 58435, 64285, 87685, 99693, 132957, 137885, 140335, 353133, 423657, 596037, 655707, 734517, 745503, 894387, 1390753, 1406427, 1529983, 1641783, 1739507, 1823877
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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(15) = 24 = phi(3 * 15), so 15 is a term of the sequence.
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MATHEMATICA
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Select[ Range[1936556], EulerPhi[3# ] == DivisorSigma[1, # ] &]
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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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