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A108121 A three-symbol substitution sequence with characteristic polynomial: x^3-x^2-2*x-1. 0
3, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 1, 2, 2, 3, 2, 3, 3, 1, 2, 2, 3, 3, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 1, 2, 2, 3, 2, 3, 3, 1, 2, 2, 3, 3, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 1, 2, 2, 3, 2, 3, 3, 1, 2, 2, 3, 3, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

This substitution is unique in that it gives a two part tile that only tiles aperiodically.

LINKS

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

FORMULA

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

MATHEMATICA

s[1] = {2}; s[2] = {3}; s[3] = {1, 2, 2, 3}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] aa = p[8]

CROSSREFS

Sequence in context: A144148 A085247 A003016 * A161916 A072548 A079399

Adjacent sequences:  A108118 A108119 A108120 * A108122 A108123 A108124

KEYWORD

nonn,uned

AUTHOR

Roger L. Bagula, Jun 04 2005

STATUS

approved

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Last modified March 22 10:07 EDT 2019. Contains 321421 sequences. (Running on oeis4.)