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 A105315 Limited tetrahedron digraph 4-symbol substitution : characteristic polynomial: x^4-2*x-1. Each edge is taken only once. 0

%I

%S 1,1,2,3,1,2,3,2,3,3,4,4,1,2,3,2,3,3,4,4,2,3,3,4,4,3,4,4,4,1,1,1,2,3,

%T 2,3,3,4,4,2,3,3,4,4,3,4,4,4,1,1,2,3,3,4,4,3,4,4,4,1,1,3,4,4,4,1,1,4,

%U 1,1,1,2,3,2,3,1,2,3,2,3,3,4,4,2,3,3,4,4,3,4,4,4,1,1,2,3,3,4,4,3,4,4,4,1,1

%N Limited tetrahedron digraph 4-symbol substitution : characteristic polynomial: x^4-2*x-1. Each edge is taken only once.

%C I've found two other matrix isomers of this sequence with the same characteristic polynomial: 1->{2,3} 2->{3} 3-{4} 4->{1,2} and: 1->{2,4} 2->{3} 3->{1,4} 4->{2}

%F 1->{2, 3}, 2->{3, 4}, 3->{4}, 4->{1}

%t s[1] = {2, 3}; s[2] = {3, 4}; s[3] = {4}; s[4] = {1}; t[a_] := Join[a, Flatten[s /@ a]]; p[0] = {1}; p[1] = t[{1}]; p[n_] := t[p[n - 1]] aa = Flatten[Table[p[n], {n, 0, 4}]]

%K nonn

%O 0,3

%A _Roger L. Bagula_, Apr 25 2005

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Last modified January 16 16:17 EST 2022. Contains 350376 sequences. (Running on oeis4.)