%I #19 Jun 25 2022 10:03:38
%S 1,4,4,3,4,3,3,2,4,3,3,2,3,2,2,1,4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,4,4,3,
%T 3,2,3,2,2,1,3,2,2,1,2,1,1,4,3,2,2,1,2,1,1,4,2,1,1,4,1,4,4,3,4,3,3,2,
%U 3,2,2,1,3,2,2,1,2,1,1,4,3,2,2,1,2,1,1,4,2,1,1,4,1,4,4,3,3,2,2,1,2,1,1,4,2,1,1,4,1,4,4,3,2,1,1
%N Image of 1 under the repeated morphism 1 -> 21, 2 -> 32, 3 -> 43, 4 -> 14.
%H F. M. Dekking, <a href="http://dx.doi.org/10.1016/0001-8708(82)90066-4">Recurrent Sets</a>, Advances in Mathematics, vol. 44, no.1, April 1982, page 85, section 4.1.
%t s[1] = {2, 1};
%t s[2] = {3, 2};
%t s[3] = {4, 3};
%t s[4] = {1, 4};
%t t[a_] := Flatten[s /@ a];
%t p[0] = {1};
%t p[1] = t[p[0]];
%t p[n_] := t[p[n - 1]]
%t aa = p[8]
%K nonn,easy
%O 0,2
%A _Roger L. Bagula_, May 07 2005
%E Edited and new name from _Joerg Arndt_, Jun 25 2022