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A097001
A062402(x)=sigma(phi[x]) function is iterated; initial value=2^n; a(n)=largest term of trajectory.
0
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
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
KEYWORD
nonn
AUTHOR
Labos Elemer, Jul 21 2004
STATUS
approved