cp's OEIS Frontend

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.

%I A253718 #7 May 06 2015 09:48:24
%S A253718 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,
%T A253718 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,
%U A253718 9,9,9,10,10,9,10,10,8,9,9,9,10,10,9,10,10
%N 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.
%C A253718 This is column 1 of the array at A253281.
%H A253718 Clark Kimberling, <a href="/A253718/b253718.txt">Table of n, a(n) for n = 0..1000</a>
%t A253718 f[{x_, y_}] := If[IntegerQ[x/3], {y, x/3}, {x - Mod[x, 3], y}];
%t A253718 g[{x_, y_}] := Drop[FixedPointList[f, {x, y}], -1];
%t A253718 Table[-1 + Length[g[{n, 0}]], {n, 0, 200}]  (* A253718 *)
%Y A253718 Cf. A253281.
%K A253718 nonn,easy
%O A253718 0,4
%A A253718 _Clark Kimberling_, May 02 2015