A096999 A062401(x)=phi[sigma(x)] function is iterated; initial value=2^n; a(n)=largest term of trajectory.

2, 6, 8, 30, 96, 126, 128, 480, 600, 3840, 2048, 8190, 10584, 27000, 32768, 196560, 311040, 851840, 1161216, 2250600, 2640704, 150992640, 150992640, 283740364800, 283740364800, 283740364800, 283740364800, 7608287232, 7608287232

Offset: 1

Author

Labos Elemer, Jul 21 2004

Keywords

• nonn

Examples

			n=8: 2^n=256, list={256,432,480,432,...}, max=a(8)=480
		

Crossrefs

Cf. A000010, A000203, A062401, A096852.

Programs

Mathematica

fs[x_] :=EulerPhi[DivisorSigma[1, x]] itef[x_, hos_] :=NestList[fs, x, hos] Table[Max[itef[2^w, 200]], {w, 1, 30}]