%I #10 Sep 20 2023 01:58:22
%S 2,4,3,1,2,2,2,4,3,1,4,3,1,4,3,1,2,2,2,2,2,2,2,2,2,4,3,1,4,3,1,4,3,1,
%T 4,3,1,4,3,1,4,3,1,4,3,1,4,3,1,4,3,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
%U 2,2,2,2,2,2,2,2,2,2,2,4,3,1,4,3,1,4,3,1,4,3,1,4,3,1,4,3,1,4,3,1,4,3,1,4,3
%N Alternating two level four-symbol substitution: characteristic polynomial: x^2*(x^2-3).
%C A triangle shaped digraph with one central point. Triangular levels as: {2}, {4, 3, 1}, {2, 2, 2}, {4, 3, 1, 4, 3, 1, 4, 3, 1}, {2, 2, 2, 2, 2, 2, 2, 2, 2}, {4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3,1, 4, 3,1}, {2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,2, 2, 2,2}
%F 1->{2}, 2->{4, 3, 1}, 3->{2}, 4->{2}.
%t s[1] = {2}; s[2] = {4, 3, 1}; s[3] = {2}; s[4] = {2};
%t t[a_] := Flatten[s /@ a];
%t p[0] = {2}; p[n_] := t[p[n - 1]];
%t Table[p[i], {i, 0, 7}]//Flatten
%K nonn,uned
%O 0,1
%A _Roger L. Bagula_, May 09 2005
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