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A135239
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Numbers m such that sigma(phi(m)) = 2*m.
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1
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OFFSET
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1,1
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COMMENTS
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No other terms below 3*10^11.
If a term m is odd, then phi(m) belongs to A001229; otherwise phi(m) belongs to A135240. (End)
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LINKS
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EXAMPLE
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sigma(phi(222850677)) = sigma(118879488) = 445701354 = 2*222850677, so 222850677 is in the sequence.
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MATHEMATICA
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Do[If[DivisorSigma[1, EulerPhi[n]]==2n, Print[n]], {n, 420000000}]
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CROSSREFS
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KEYWORD
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more,nonn
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AUTHOR
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STATUS
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approved
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