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Search: id:A074869
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| A074869 |
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Numbers n such that sigma(sigma(n) - phi(n)) = phi(n). |
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+0
1
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| 707, 7843, 143591, 274211, 598787, 737807, 861749, 928421
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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sigma(sigma(707)-phi(707)) = sigma(816-600) = sigma(216) = 600 = phi(707), so 707 is a term of the sequence.
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MATHEMATICA
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Select[Range[2, 10^6], DivisorSigma[1, DivisorSigma[1, # ] - EulerPhi[ # ]] == EulerPhi[ # ] &]
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CROSSREFS
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Adjacent sequences: A074866 A074867 A074868 this_sequence A074870 A074871 A074872
Sequence in context: A091553 A126830 A005845 this_sequence A059312 A114923 A057849
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KEYWORD
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nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Sep 12 2002
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