%I #5 Mar 30 2012 17:34:15
%S 1,5,6,3,1,2,5,5,6,4,3,3,1,2,2,5,5,5,6,4,4,3,3,3,1,2,2,2,5,5,5,5,6,4,
%T 4,4,3,3,3,3,1,2,2,2,2,5,5,5,5,5,6,4,4,4,4,3,3,3,3,3,1,2,2,2,2,2,5,5,
%U 5,5,5,5,6,4,4,4,4,4,3,3,3,3,3,3,1,2,2,2,2,2,2,5,5,5,5,5,5,5,6,4,4,4,4,4,4
%N Two block six-symbol substitution : n=1.
%C Removing two links in the digraph makes it a line. Characteristic Polynomial:x^6-3*x^4+3*x^2-1 Triangular form: ( half even/ half odd) {1}, {5, 6}, {3, 1, 2} {5, 5, 6, 4} {3, 3, 1, 2, 2} {5, 5, 5, 6, 4, 4} {3, 3, 3, 1, 2, 2, 2} {5, 5, 5, 5, 6, 4, 4, 4}
%D Curtis McMullen, Prym varieties and Teichmuller curves.
%F 1->{5, 6}, 2->{}4}*n, 3->{5}, 4->{2}, 5->{3}*n, 6->{1, 2}
%t n0=6;n=1; s[1] = {5, 6};s[2] = Table[If[i <= n, 4, {}], {i, 1, n0}]; s[3] = Table[If[i <= n, 5, {}], {i, 1, n0}]; s[4] = Table[If[i <= n, 2, {}], {i, 1, n0}];; s[5] = Table[If[i <= n, 3, {}], {i, 1, n0}]; s[6] = {1, 2}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] aa = Table[p[i], {i, 0, 20}]; MatrixForm[aa] aaa = Flatten[aa]
%K nonn,uned
%O 0,2
%A _Roger L. Bagula_, May 10 2005