%I
%S 2,3,4,3,4,1,4,3,4,1,2,1,4,1,4,3,4,1,2,1,2,3,2,1,4,1,2,1,4,1,4,3,4,1,
%T 2,1,2,3,2,1,2,3,4,3,2,3,2,1,4,1,2,1,2,3,2,1,4,1,2,1,4,1,4,3,4,1,2,1,
%U 2,3,2,1,2,3,4,3,2,3,2,1,2,3,4,3,4,1,4,3,2,3,4,3,2,3,2,1,4,1,2,1,2,3,2,1,2
%N Trajectory of 1 under the morphism 1>{2,1}, 2>{2,3}, 3>{4,3}, 4>{4,1}.
%C This is the reverse of the morphism in A105500 and the trajectory of 1 actually starts with 2 instead of 1.
%H F. M. Dekking, <a href="http://dx.doi.org/10.1016/00018708(82)900664">Recurrent sets</a>, Advances in Mathematics, vol. 44, no. 1 (1982), 78104.
%H <a href="/index/Fi#FIXEDPOINTS">Index entries for sequences that are fixed points of mappings</a>
%t Nest[ Flatten[ # /. {1 > {2, 1}, 2 > {2, 3}, 3 > {4, 3}, 4 > {4, 1}}] &, {1}, 8] (*_Robert G. Wilson v_, Jun 20 2005 *)
%o (PARI) {a(n)=local(A);if(n<0, 0, n++; A=[2]; while(length(A)<n, A=concat(vector(length(A),k,[[2,1],[2,3],[4,3],[4,1]][A[k]]))); A[n])}
%Y Cf. A105500.
%K nonn,easy
%O 0,1
%A _N. J. A. Sloane_, May 20 2005
