cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A143668 Result of the morphing 01->01021212, 02->0102121201, 12->01021201, iterated from '01'. Sequence of the Fibonacci word fractal.

Original entry on oeis.org

0, 1, 0, 2, 1, 2, 1, 2, 0, 1, 0, 2, 1, 2, 1, 2, 0, 1, 0, 1, 0, 2, 1, 2, 0, 1, 0, 1, 0, 2, 1, 2, 0, 1, 0, 1, 0, 2, 1, 2, 1, 2, 0, 1, 0, 2, 1, 2, 1, 2, 0, 1, 0, 1, 0, 2, 1, 2, 0, 1, 0, 1, 0, 2, 1, 2, 0, 1, 0, 1, 0, 2, 1, 2, 1, 2, 0, 1, 0, 2, 1, 2, 1, 2, 0, 1, 0, 2, 1, 2, 1, 2, 0, 1, 0, 1, 0, 2, 1, 2
Offset: 1

Views

Author

Keywords

Comments

Letter '2' is always in an even position and '0' an odd position.
When replacing '2' by '0', equals the infinite Fibonacci word (see A003849).
This sequence produces the Fibonacci word fractal when applying the following turtle graphics rules: 0->draw segment+turn right, 1-> draw segment, 2-> draw segment+turn left (A. Monnerot-Dumaine 2008 see links).
This sequence is the [1->12, 2->01, 3->02]-transform of A123564. - Michel Dekking, Mar 03 2018

References

  • M. Lothaire, Combinatorics on words, Cambridge University press.

Crossrefs

Formula

Let (b(n)) be the infinite Fibonacci word. if (b(n)=0 and n is even), then a(n)=2, else a(n)=b(n).