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A096859 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). +0
9
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; listen)
OFFSET

1,3

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.

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)

CROSSREFS

Cf. A062401, A062402, A095955, A096860-A096864.

Sequence in context: A067089 A090872 A063473 this_sequence A005086 A157372 A020649

Adjacent sequences: A096856 A096857 A096858 this_sequence A096860 A096861 A096862

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Jul 21 2004

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Last modified November 27 14:50 EST 2009. Contains 167570 sequences.


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