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A089693
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Numbers n such that phi(n) = 2^bigomega(n).
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1
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1, 3, 10, 20, 30, 40, 60, 80, 120, 160, 240, 320, 480, 640, 960, 1280, 1920, 2560, 3840, 5120, 7680, 10240, 15360, 20480, 30720, 40960, 61440, 81920, 122880, 163840, 245760, 327680, 491520, 655360, 983040
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OFFSET
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1,2
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LINKS
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FORMULA
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MATHEMATICA
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Select[Range[100000], EulerPhi[#]==2^PrimeOmega[#]&] (* or *) Join[{1, 3, 10}, LinearRecurrence[{0, 2}, {20, 30}, 20]] (* Harvey P. Dale, Mar 01 2012 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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