A106655 - OEIS

A106655

Four-symbol substitution, characteristic polynomial: x^4-x^3-1.

4, 3, 2, 1, 4, 3, 2, 1, 4, 2, 1, 4, 1, 4, 4, 3, 2, 1, 4, 3, 2, 1, 4, 2, 1, 4, 1, 4, 4, 3, 2, 1, 4, 2, 1, 4, 1, 4, 4, 3, 2, 1, 4, 1, 4, 4, 3, 2, 1, 4, 4, 3, 2, 1, 4, 3, 2, 1, 4, 2, 1, 4, 1, 4, 4, 3, 2, 1, 4, 3, 2, 1, 4, 2, 1, 4, 1, 4, 4, 3, 2, 1, 4, 2, 1, 4, 1, 4, 4, 3, 2, 1, 4, 1, 4, 4, 3, 2, 1, 4, 4, 3, 2, 1, 4

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OFFSET

0,1

COMMENTS

This substitution is associated with the Theta(1) Pisot number. Digraph matrix is: {{0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}, {1, 0, 0, 1}}

LINKS

Table of n, a(n) for n=0..104.

FORMULA

1->{2}, 2->{3}, 3->{4}, 5->{1, 4}

MATHEMATICA

s[1] = {2}; s[2] = {3}; s[3] = {4}; s[4] = {1, 2, 3}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] aa = p[19]

CROSSREFS