A123609 Quasiperiodic 9-gonal (nonagonal) sequence as a 1-dimensional tiling.
4, 1, 2, 3, 4, 4, 3, 4, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 2, 3, 4, 1, 2, 3, 4, 3, 4, 2, 3, 4, 1, 2, 3, 4, 4, 3, 4, 2, 3, 4, 1, 2, 3, 4
Offset: 1
Examples
1=>4, then 4=>1,2,3,4, which, in turn, generates 4,3,4,2,3,4,1,2,3,4 (append next result to right of previous result, getting an infinite aperiodic sequence).
Links
- P. Steinbach, Golden fields: a case for the heptagon, Math. Mag. 70 (1997), no. 1, 22-31, p. 29.
Programs
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Mathematica
Drop[SubstitutionSystem[{1->{4},2->{3,4},3->{2,3,4},4->{1,2,3,4}},{1},{5}][[1]],5] (* Harvey P. Dale, Mar 02 2022 *)
Formula
Using the seed "1", we use the recurrence rules 1=>4; 2=>3,4; 3=>2,3,4; 4=>1,2,3,4; to form iterative subsets which are appended in succession to form a continuous string.
Extensions
Partially edited by Jon E. Schoenfield, Sep 15 2013
Comments