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A066516
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Numbers n such that g(sigma(n)) = phi(n), where g(n) = prime(n+1) - prime(n).
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0
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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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EXAMPLE
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g(sigma(4)) = g(7) = prime(8)-prime(7) = 19-17 = 2 = phi(4).
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MATHEMATICA
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g[x_] := Prime[x + 1] - Prime[x]; Select[Range[1, 10^5], g[DivisorSigma[1, # ]] == EulerPhi[ # ] &]
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CROSSREFS
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KEYWORD
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nonn,fini,full
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AUTHOR
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STATUS
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approved
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