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 A106645 A four-symbol substitution with characteristic polynomial x^4-x-1. 0
 2, 4, 1, 2, 4, 1, 3, 1, 2, 4, 1, 2, 4, 1, 3, 1, 3, 4, 3, 1, 3, 1, 2, 4, 1, 2, 4, 1, 3, 1, 2, 4, 1, 2, 4, 1, 3, 1, 3, 4, 3, 1, 3, 1, 3, 4, 3, 2, 4, 3, 4, 3, 1, 3, 1, 3, 4, 3, 1, 3, 1, 2, 4, 1, 2, 4, 1, 3, 1, 2, 4, 1, 2, 4, 1, 3, 1, 3, 4, 3, 1, 3, 1, 2, 4, 1, 2, 4, 1, 3, 1, 2, 4, 1, 2, 4, 1, 3, 1, 3, 4, 3, 1, 3, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS A minimal Pisot like substitution, but in 4 symbols. LINKS FORMULA 1->{2, 4}, 2->{3, 4}, 3->{1}, 4->{3} MATHEMATICA s[1] = {2, 4}; s[2] = {3, 4}; s[3] = {1}; s[4] = {3}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] aa = p[16] CROSSREFS Sequence in context: A124911 A132954 A069705 * A115314 A062039 A035492 Adjacent sequences:  A106642 A106643 A106644 * A106646 A106647 A106648 KEYWORD nonn,uned AUTHOR Roger L. Bagula, May 12 2005 STATUS approved

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Last modified March 30 10:31 EDT 2020. Contains 333125 sequences. (Running on oeis4.)