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A096859
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Function A062401(x)=phi(sigma(x))=f(x) is iterated. Starting with n, a(n) is the count of distinct terms arising in trajectory; a(n)=t(n)+c(n)=t+c, where t=number of transient terms, c=number of recurrent terms (in the terminal cycle).
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8
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1, 1, 2, 2, 2, 2, 3, 1, 2, 3, 3, 1, 3, 2, 2, 3, 3, 4, 2, 2, 4, 2, 2, 3, 4, 2, 4, 4, 2, 3, 4, 4, 4, 5, 4, 3, 5, 4, 4, 4, 2, 5, 3, 4, 4, 4, 4, 2, 4, 3, 4, 6, 5, 5, 4, 5, 5, 4, 4, 2, 4, 5, 3, 4, 4, 3, 5, 4, 5, 3, 4, 2, 4, 4, 3, 3, 5, 3, 5, 3, 4, 4, 4, 3, 4, 5, 5, 3, 4, 3, 3, 3, 5, 3, 5, 2, 6, 4, 3, 7, 5, 3, 3, 3, 5
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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EXAMPLE
| n=255: list={255,144,360,288,[432,480],432,.},t=transient=4,c=cycle=2, a[255]=t+c=6;
n=244: list={244,180,144,360,288,[432,480],432,..},t=5,c=2,a[244]=7.
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MATHEMATICA
| fs[x_] :=EulerPhi[DivisorSigma[1, x]] itef[x_, len_] :=NestList[fs, x, len] Table[Length[Union[itef[2^w, 20]]], {w, 1, 256}] (len=20 at n<=256 is suitable)
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CROSSREFS
| Cf. A062401, A062402, A095955, A096860-A096864.
Sequence in context: A194330 A194286 A063473 * A005086 A157372 A020649
Adjacent sequences: A096856 A096857 A096858 * A096860 A096861 A096862
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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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