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.

A364121 Stolarsky representation of n.

Original entry on oeis.org

0, 1, 11, 10, 111, 101, 110, 1111, 100, 1011, 1101, 1110, 11111, 1010, 1001, 10111, 1100, 11011, 11101, 11110, 111111, 1000, 10101, 10011, 10110, 101111, 11010, 11001, 110111, 11100, 111011, 111101, 111110, 1111111, 10100, 10001, 101011, 10010, 100111, 101101
Offset: 1

Views

Author

Amiram Eldar, Jul 07 2023

Keywords

Crossrefs

Programs

  • Mathematica
    stol[n_] := stol[n] = If[n == 1, {}, If[n != Round[Round[n/GoldenRatio]*GoldenRatio], Join[stol[Floor[n/GoldenRatio^2] + 1], {0}], Join[stol[Round[n/GoldenRatio]], {1}]]];
    a[n_] := FromDigits[stol[n]]; Array[a, 100]
  • PARI
    stol(n) = {my(phi=quadgen(5)); if(n==1, [], if(n != round(round(n/phi)*phi), concat(stol(floor(n/phi^2) + 1), [0]), concat(stol(round(n/phi)), [1])));}
    a(n) = fromdigits(stol(n));

Formula

Description of an algorithm for calculating a(n):
Let s(1) = {} be the empty set, and for n > 1, let s(n) be the sequence of digits of a(n). s(n) can be calculated recursively by:
1. If n = round(round(n/phi)*phi) then s(n) = s(floor(n/phi^2) + 1) U {0}, where phi is the golden ratio (A001622) and U denotes concatenation.
2. If n != round(round(n/phi)*phi) then s(n) = s(round(n/phi)) U {1}.
a(n) = A007088(A200714(n)).
A268643(a(n)) = A200649(n).
A055641(a(n)) = A200650(n).
A055642(a(n)) = A200648(n).
A043562(a(n)) = A200651(n)