A097001 A062402(x)=sigma(phi[x]) function is iterated; initial value=2^n; a(n)=largest term of trajectory.

2, 4, 12, 16, 72, 252, 312, 256, 1512, 1860, 12264, 6552, 26208, 34200, 93600, 65536, 833280, 1116024, 2239920, 4464096, 9865440, 8124480, 569540160, 569540160, 1100946774480, 1100946774480, 1100946774480, 1100946774480, 34696672920

Offset

1,1

Links

Table of n, a(n) for n=1..29.

Example

n=13: 2^n=8192, list={8192,8191,26208,[20440],20440,.. a[13]=26208 arose in transient.

Mathematica

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

Crossrefs

Cf. A000010, A000203, A062402, A096852.

Sequence in context: A308076 A303819 A074646 * A233191 A192533 A371278

Adjacent sequences: A096998 A096999 A097000 * A097002 A097003 A097004

Keyword

nonn

Author

Labos Elemer, Jul 21 2004

Status

approved