A253718 Number h such that (h,0) is n steps from (0,0), where steps are as follows: (x,y)->(x-r, y) if r > 0, and (x,y)->(y, r/3) otherwise, where r = x mod 3.

0, 1, 1, 3, 4, 4, 3, 4, 4, 5, 6, 6, 6, 7, 7, 6, 7, 7, 5, 6, 6, 6, 7, 7, 6, 7, 7, 7, 8, 8, 8, 9, 9, 8, 9, 9, 8, 9, 9, 9, 10, 10, 9, 10, 10, 8, 9, 9, 9, 10, 10, 9, 10, 10, 7, 8, 8, 8, 9, 9, 8, 9, 9, 8, 9, 9, 9, 10, 10, 9, 10, 10, 8, 9, 9, 9, 10, 10, 9, 10, 10

Offset

0,4

Comments

This is column 1 of the array at A253281.

Links

Clark Kimberling, Table of n, a(n) for n = 0..1000

Mathematica

f[{x_, y_}] := If[IntegerQ[x/3], {y, x/3}, {x - Mod[x, 3], y}];
g[{x_, y_}] := Drop[FixedPointList[f, {x, y}], -1];
Table[-1 + Length[g[{n, 0}]], {n, 0, 200}]  (* A253718 *)

Crossrefs

Cf. A253281.

Sequence in context: A370454 A306477 A276865 * A350188 A374363 A295570

Adjacent sequences: A253715 A253716 A253717 * A253719 A253720 A253721

Keyword

nonn,easy

Author

Clark Kimberling, May 02 2015

Status

approved