A258236 Number of steps from n to 0, where allowable steps are x -> [x/r] if x is in upper Wythoff sequence (A001950) and x -> [r*x] otherwise, where [ ] = floor and r = (3+sqrt(5))/2.

0, 2, 1, 3, 5, 3, 5, 2, 4, 6, 4, 6, 8, 6, 8, 4, 6, 8, 6, 8, 3, 5, 7, 5, 7, 9, 7, 9, 5, 7, 9, 7, 9, 11, 9, 11, 7, 9, 11, 9, 11, 5, 7, 9, 7, 9, 11, 9, 11, 7, 9, 11, 9, 11, 4, 6, 8, 6, 8, 10, 8, 10, 6, 8, 10, 8, 10, 12, 10, 12, 8, 10, 12, 10, 12, 6, 8, 10, 8

Offset

0,2

Comments

a(n) = number of edges from 0 to n in the tree at A258235.

Links

Clark Kimberling, Table of n, a(n) for n = 0..10000

Example

29->75->28->10->3->7->2->0, so that a(29) = 7.

Mathematica

r = GoldenRatio^2; 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}]

Crossrefs

Cf. A258235, A258212, A001950.

Sequence in context: A209152 A209158 A209135 * A258244 A258248 A209139

Adjacent sequences: A258233 A258234 A258235 * A258237 A258238 A258239

Keyword

nonn,easy

Author

Clark Kimberling, Jun 05 2015

Status

approved