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

30, 42, 54, 100, 140, 148, 194, 196, 208, 220, 238, 252, 274, 288, 300, 336, 348, 350, 364, 374, 380, 382, 386, 400, 420, 440, 492, 516, 528, 540, 542, 550, 592, 600, 612, 660, 694, 708, 720, 722, 740, 756, 758, 764, 766, 780, 792, 794, 820, 836, 900, 932

Offset: 1

Author

Labos Elemer, Aug 30 2004

Keywords

• nonn

Examples

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

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1000

Crossrefs

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

Programs

Mathematica

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 *)