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.

A258242 Number of steps from n to 0, where allowable steps are x -> [x/r] if x = is in A022838 (the Beatty sequence for sqrt(3)) and x -> [r*x] otherwise, where [ ] = floor and r = sqrt(3).

Original entry on oeis.org

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

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Author

Clark Kimberling, Jun 07 2015

Keywords

Comments

a(n) = number of edges from 0 to n in the tree at A258241.

Examples

			16->27->15->8->4->6->3->1->0, so that a(16) = 8.
		

Crossrefs

Programs

  • Mathematica
    r = Sqrt[3]; w = Table[Floor[r*n], {n, 1, 1000}];
    f[x_] := If[MemberQ[w, x], Floor[x/r], Floor[r*x]];
    g[x_] := Drop[FixedPointList[f, x], -1];
    Table[-1+ Length[g[n]], {n, 0, 100}]