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A078166
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Numbers n such that phi(n) is a perfect sixth power.
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8
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1, 2, 85, 128, 136, 160, 170, 192, 204, 240, 4369, 8192, 8224, 8704, 8738, 10240, 10280, 10880, 12288, 12336, 13056, 15360, 15420, 16320, 47197, 47239, 47989, 49267, 49589, 50557, 51319, 52429, 52649, 55699, 57589, 57953, 59495, 63973
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..38.
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EXAMPLE
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phi of the sequence includes 1,64,4096,46656,..; powers arise several times; a(3)=A053576[6]=85; in sequence relatively large jumps are observable when power of new numbers appear.
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MATHEMATICA
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k=6; Select[Range[65000], IntegerQ[EulerPhi[#]^(1/k)]&] (* From Harvey P. Dale, Feb 20 2011 *)
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CROSSREFS
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Cf. A039770[square], A039771[cube], A078164[4th], A078165[5th], A078166[6th], A078167[7th], A078168[8th], A078169[9th], A078170[10th power], A001317, A053576, A045544, A000010.
Sequence in context: A157063 A181119 A157315 * A101578 A041881 A076542
Adjacent sequences: A078163 A078164 A078165 * A078167 A078168 A078169
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Nov 27 2002
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STATUS
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approved
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