OFFSET
1,2
COMMENTS
If the trajectory of n contains two consecutive non-multiples of 3 then it increases for ever [te Riele].
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
H. J. J. te Riele, Iteration of number-theoretic functions, Nieuw Archief v. Wiskunde, (4) 1 (1983), 345-360. See Example III.3.
MATHEMATICA
f[n_] := If[Divisible[n, 3], n/3, Floor[n*Sqrt[3]]]; a[n_] := Module[{k = n, inc = False, c = 0}, While[k > 1, kk = f[k]; If[inc && kk > k, c = -1; Break[]]; inc = kk > k; k = kk; c++]; c]; Array[a, 100]; (* Amiram Eldar, Mar 17 2019 *)
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Mar 17 2019
EXTENSIONS
More terms from Amiram Eldar, Mar 17 2019
STATUS
approved