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A077091
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When iteration of f[]=Phi[](Sigma[]-Phi[]) is started at composite initial values listed here it ends at a nonzero fixed point.
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2
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1, 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 38, 39, 42, 44, 45, 46, 49, 51, 54, 55, 56, 57, 58, 62, 63, 65, 68, 69, 70, 74, 75, 77, 82, 85, 86, 87, 91, 93, 94, 95, 99, 104, 111, 115, 119, 121, 125, 129, 133, 134, 143, 145, 153
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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EXAMPLE
| n=30: FixedPointList={30,32,46,20,16,22,12,8,10,6,4},end=4; n=94:FixedPointList={94,42,24},end=24.
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MATHEMATICA
| f[x_] := EulerPhi[DivisorSigma[1, x]-EulerPhi[x]] Do[s=NestList[f, n, 100]; s1=Part[s, 99]; s2=Part[s, 100]; If[Equal[s1, s2]&&!PrimeQ[n], Print[{n, s1}]], {n, 1, 1000}]
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CROSSREFS
| Cf. A077090-A077100.
Sequence in context: A141468 A140209 A140347 * A174891 A051035 A046349
Adjacent sequences: A077088 A077089 A077090 * A077092 A077093 A077094
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Oct 31 2002
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