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.

A332298 a(n) is the X-coordinate of the n-th point of the Fibonacci word fractal. Sequence A332299 gives Y-coordinates.

Original entry on oeis.org

0, 1, 2, 2, 3, 4, 4, 4, 3, 3, 3, 4, 4, 4, 3, 2, 2, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 2, 2, 3, 4, 4, 5, 6, 6, 6, 5, 5, 5, 6, 7, 7, 8, 9, 9, 10, 11, 11, 11, 10, 10, 10, 11, 12, 12, 13, 14, 14, 15, 16, 16, 16, 15, 15, 15, 16, 16, 16, 15, 14, 14, 13, 12, 12, 12, 13
Offset: 0

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Author

Rémy Sigrist, Feb 09 2020

Keywords

Comments

To build the curve:
- start from the origin looking to the right,
- for k=0, 1, ...:
- move forward to the next lattice point,
- if A003849(k) = 1 then:
- if k is even then turn 90 degrees to the right
- otherwise turn 90 degrees to the left.

Crossrefs

Cf. A003849, A265318, A332299 (Y-coordinates).

Programs

  • PARI
    A003849(n)=my(k=2); while(fibonacci(k)<=n, k++); while(n>1, while(fibonacci(k--)>n, ); n-=fibonacci(k)); n==1
    { z=0; d=I; for (n=0, 76, print1 (real(z) ", "); if (A003849(n)==0, if (n%2==0, d/=I, d*=I);); z+=d) }