%I A097002
%S A097002 1,3,7,15,31,63,127,255,511,1023,2047,4095,8191,6045,24552,65535,131071,
%T A097002 262143,524287,1048575,2097151,4194303,8388607,16777215,33554431,
%U A097002 67108863,134217727,268435455,536870911,1073741823
%N A097002 A062402(x)=sigma(phi[x]) function is iterated; initial value=2^n; a(n)=smallest 
               term of trajectory.
%e A097002 n=13: 2^n=8192, trajectory ={8192, 8191, 26208, [20440], 20440, .. a[13]=8191 
               arose in transient.
%t A097002 gf[x_] :=DivisorSigma[1, EulerPhi[x]] gite[x_, hos_] :=NestList[gf, x, 
               hos] Table[Min[gite[2^w, 200]], {w, 1, 30}]
%Y A097002 Cf. A000010, A000203, A062402, A096857.
%Y A097002 Sequence in context: A043755 A105755 A043764 this_sequence A060152 A126646 
               A000225
%Y A097002 Adjacent sequences: A096999 A097000 A097001 this_sequence A097003 A097004 
               A097005
%K A097002 nonn
%O A097002 1,2
%A A097002 Labos E. (labos(AT)ana.sote.hu), Jul 21 2004