%I A105777
%S A105777 1,2,2,2,1,4,3,3,3,4,4,3,3,3,4,4,3,3,3,4,1,2,2,2,1,3,4,4,4,3,2,1,1,1,2,
%T A105777 2,1,1,1,2,2,1,1,1,2,3,4,4,4,3,3,4,4,4,3,2,1,1,1,2,2,1,1,1,2,2,1,1,1,2,
%U A105777 3,4,4,4,3,3,4,4,4,3,2,1,1,1,2,2,1,1,1,2,2,1,1,1,2,3,4,4,4,3,1,2,2,2,1
%N A105777 Trajectory of 1 under the morphism 1->{1,2,2,2,1}, 2->{4,3,3,3,4}, 3->
               {2,1,1,1,2}, 4->{3,4,4,4,3}.
%C A105777 Edgar-Peano substitution of 4 symbols taken 5 at a time: characteristic 
               polynomial -x^5+5*x^3+5*x^2-25*x.
%D A105777 F. M. Dekking, Recurrent sets, Advances in Mathematics, 44 (1982), 78-104.
%D A105777 G. A. Edgar and Jeffery Golds, A Fractal Dimension Estimate for a Graph-Directed 
               IFS of Non-Similarities, 1991
%t A105777 s[1] = {1, 2, 2, 2, 1}; s[2] = {4, 3, 3, 3, 4}; s[3] = {2, 1, 1, 1, 2}; 
               s[4] = {3, 4, 4, 4, 3}; s[5] = {} t[a_] := Flatten[s /@ a]; p[0] 
               = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] aa = p[3]
%o A105777 (PARI) {a(n)=local(A); if(n<1,0, A=[1]; while(length(A)<n, A=concat(vector(length(A),
               k,[1,2,2,2,1;4,3,3,3,4;2,1,1,1,2;3,4,4,4,3][A[k],]))); A[n])} /* 
               Michael Somos May 16 2005 */
%Y A105777 Sequence in context: A127496 A144393 A089400 this_sequence A014572 A071458 
               A131308
%Y A105777 Adjacent sequences: A105774 A105775 A105776 this_sequence A105778 A105779 
               A105780
%K A105777 nonn
%O A105777 0,2
%A A105777 Roger L. Bagula (rlbagulatftn(AT)yahoo.com), May 04 2005