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A033855
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Numbers k such that j(k)*phi(k) = s(phi(k)), where j(k) = A033831(k), s(k) = sigma(k) - k.
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2
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1, 2, 7, 9, 29, 143, 155, 183, 731, 791, 1011, 1346, 35659, 60484, 65524, 525227, 525557, 525617, 526697, 529817, 531779, 567437, 1047554, 2541679, 33550337, 214486281, 1476844097, 1478227937, 1543409687, 14200144243, 14200244477, 14200257551, 14200349281, 14200779611, 14201040053, 14201501401
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OFFSET
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1,2
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COMMENTS
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LINKS
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MATHEMATICA
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j[n_] := DivisorSum[n, 1&, # > 2 && n/# < #-1 &]; aQ[n_] := j[n] * (p = EulerPhi[ n]) == DivisorSigma[1, p] - p; Select[Range[10^4], aQ] (* Amiram Eldar, Jul 01 2019 *)
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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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