A077096 Numbers k such that iterating phi(sigma(k)-phi(k)) starting from k leads to the fixed point 8064.

7530, 8064, 9678, 9828, 9990, 10002, 10290, 10464, 11000, 11004, 11172, 11350, 11510, 11572, 11814, 11930, 12006, 12192, 12348, 12472, 12636, 12654, 12726, 12750, 12772, 12972, 13332, 13372, 13420, 13440, 13626, 13648, 13656, 13695

Offset: 1

Author

Labos Elemer, Oct 31 2002

Keywords

• nonn
• more

Examples

			n=41354: FixedPointList={41354,13440,15232,8064}, end=8064.
		

Crossrefs

Cf. A077090, A077091, A077092, A077093, A077094, A077095.

Programs

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]&&Equal[s1, 8064], Print[n]], {n, 1, 1000000}]
fp[n_]:=FixedPoint[EulerPhi[DivisorSigma[1,#]-EulerPhi[#]]&,n,100]==8064; Select[ Range[14000],fp] (* Harvey P. Dale, May 05 2013 *)