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A097036 Initial values for iteration of A063919[x] function such that iteration ends in a 3-cycle. 9

%I

%S 30,42,54,100,140,148,194,196,208,220,238,252,274,288,300,336,348,350,

%T 364,374,380,382,386,400,420,440,492,516,528,540,542,550,592,600,612,

%U 660,694,708,720,722,740,756,758,764,766,780,792,794,820,836,900,932

%N Initial values for iteration of A063919[x] function such that iteration ends in a 3-cycle.

%H Amiram Eldar, <a href="/A097036/b097036.txt">Table of n, a(n) for n = 1..1000</a>

%e n=100: list={100, [30, 42, 54], 30, ... after 1 transient a 3-cycle arises.

%t s[n_] := If[n > 1, Times @@ (1 + Power @@@ FactorInteger[n]) - n, 0]; useq[n_] := Most[NestWhileList[s, n, UnsameQ, All]]; cycleQ[k_] := Module[{s1 = s[k]}, s1 != k && s[s[s1]] == k]; aQ[n_] := cycleQ[Last[useq[n]]]; Select[Range[1000], aQ] (* _Amiram Eldar_, Apr 06 2019 *)

%Y Cf. A002827, A063919, A063991, A097024, A097030-A097037.

%K nonn

%O 1,1

%A _Labos Elemer_, Aug 30 2004

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Last modified January 22 13:41 EST 2020. Contains 331149 sequences. (Running on oeis4.)