Search: id:A108121 Results 1-1 of 1 results found. %I A108121 %S A108121 3,1,2,2,3,1,2,2,3,2,3,3,1,2,2,3,1,2,2,3,2,3,3,1,2,2,3,2,3,3,1,2,2,3,3, %T A108121 1,2,2,3,1,2,2,3,2,3,3,1,2,2,3,1,2,2,3,2,3,3,1,2,2,3,2,3,3,1,2,2,3,3,1, %U A108121 2,2,3,1,2,2,3,2,3,3,1,2,2,3,2,3,3,1,2,2,3,3,1,2,2,3,1,2,2,3,2,3,3,1,2 %N A108121 A three-symbol substitution sequence with characteristic polynomial: x^3-x^2-2*x-1. %C A108121 This substitution is unique in that it gives a two part tile that only tiles aperiodically. %F A108121 1->{2}, 2->{3}, 3->{1, 2, 2, 3} %t A108121 s[1] = {2}; s[2] = {3}; s[3] = {1, 2, 2, 3}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] aa = p[8] %Y A108121 Sequence in context: A144148 A085247 A003016 this_sequence A161916 A072548 A079399 %Y A108121 Adjacent sequences: A108118 A108119 A108120 this_sequence A108122 A108123 A108124 %K A108121 nonn,uned %O A108121 0,1 %A A108121 Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Jun 04 2005 Search completed in 0.001 seconds