%I #7 Jun 15 2013 01:33:22
%S 1,11,17,19,23,25,29,31,49,77,85,95,97,113,115,119,121,131,139,145,
%T 179,181,185,193,217,311,313,371,385,407,431,451,467,473,475,485,491,
%U 493,503,527,601,605,641,695,697,791,805,847,973,1163,1219,1241,1295,1417
%N Positive integers k with at least one primitive cycle of positive integers under iteration by the 3x-k function.
%C A cycle is called primitive if its elements are not a common multiple of the elements of another cycle.
%C The 3x-k function T_k is defined by T_k(x) = x/2 if x is even, (3x-k)/2 if x is odd. GCD(k,6)=1.
%H Geoffrey H. Morley, <a href="/A226630/b226630.txt">Table of n, a(n) for n = 1..600</a>
%Y Cf. A226633.
%K nonn
%O 1,2
%A _Geoffrey H. Morley_, Jun 13 2013