%I A077094
%S A077094 4,6,8,9,10,12,14,15,16,18,20,21,22,25,26,27,28,30,32,33,34,35,38,39,
%T A077094 44,45,46,49,51,54,55,56,57,58,62,63,65,68,70,77,85,87,91,93,95,99,104,
%U A077094 111,119,121,129,134,143,145,153,158,161,169,189,205,209,215,221,245
%N A077094 Starting the iteration of the function Phi[]*(Sigma[]-Phi[]) at these 
               initial values leads to the fixed point 4.
%C A077094 Probably this sequence is finite, with 92 terms of which the last is 
               6241.
%e A077094 n=6241: FixedPointList={6241,104,54,32,20,16,22,12,8,10,6,4},end=4.
%t A077094 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]&&Equal[s1, 
               4], Print[{n, s1}]], {n, 1, 1000000}]
%Y A077094 Cf. A077090-A077100.
%Y A077094 Sequence in context: A046349 A115683 A091212 this_sequence A070807 A046352 
               A046355
%Y A077094 Adjacent sequences: A077091 A077092 A077093 this_sequence A077095 A077096 
               A077097
%K A077094 nonn,fini
%O A077094 1,1
%A A077094 Labos E. (labos(AT)ana.sote.hu), Oct 31 2002