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A097004
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Function A062402[x]=phi[sigma[x]] is iterated. Starting with 2^n, the n-th power of 2, a(n) is the count of distinct terms arising in trajectory; a(n)=t(n)+c(n)=t+c, where t is the number of transient terms, c is the number of recurrent terms [in the terminal cycle].
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1
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1, 2, 2, 3, 2, 4, 5, 5, 2, 4, 5, 11, 4, 4, 12, 17, 2, 8, 11, 14, 26, 11, 6, 80, 59, 100, 101, 95, 93, 60, 38, 55, 2
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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EXAMPLE
| n=13:2^n=8192,trajectory ={8192,8191,26208,[20440],.. }, a[13]=3+1=4 with 3 tranients and one recurrent term.
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MATHEMATICA
| EulerPhi[DivisorSigma[1, x]] itef[x_, len_] :=NestList[fs, x, len] Table[Length[Union[itef[2^w, 1000]]], {w, 1, 256}]
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CROSSREFS
| Cf. A000010, A000203, A062402, A096852, A096857.
Sequence in context: A144369 A033822 A144428 * A053023 A153725 A102247
Adjacent sequences: A097001 A097002 A097003 * A097005 A097006 A097007
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Jul 21 2004
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