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A053577
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Cototient function ( n-EulerPhi[n] ) is a power of 2.
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4
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2, 3, 4, 5, 6, 7, 8, 11, 12, 13, 14, 16, 17, 19, 23, 24, 28, 29, 31, 32, 37, 41, 43, 47, 48, 53, 56, 59, 61, 62, 64, 67, 71, 73, 79, 83, 89, 96, 97, 101, 103, 107, 109, 112, 113, 124, 127, 128, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 192, 193, 197
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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FORMULA
| A051953[n]=2^w
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EXAMPLE
| For p prime cototient[p]=1; for x in the set {49152,57344,63488,65024,65528,65536}, x-Phi[x]=2^15=32768.
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MATHEMATICA
| Select[Range[200], IntegerQ[Log[2, #-EulerPhi[#]]]&] (* From Harvey P. Dale, Dec 14 2011 *)
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CROSSREFS
| Cf. A051953, A053578.
Sequence in context: A032847 A023778 A173016 * A093515 A084369 A167211
Adjacent sequences: A053574 A053575 A053576 * A053578 A053579 A053580
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Jan 18 2000
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