%N Ordered set S defined by these rules: 0 and 1 are in S and if x is a nonzero number in S, then 3x-1 and 9x are in S.
%C The numbers 1 and 9x occupy same positions in S that 1 occupies in the infinite Fibonacci word (A003849).
%H Ivan Neretin, <a href="/A060139/b060139.txt">Table of n, a(n) for n = 0..10000</a>
%H Clark Kimberling, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL3/goldentext.html">A Self-Generating Set and the Golden Mean</a>, J. Integer Sequences, 3 (2000), #00.2.8.
%H Clark Kimberling, <a href="https://www.fq.math.ca/Papers1/52-3/Kimberling11132013.pdf">Fusion, Fission, and Factors</a>, Fib. Q., 52 (2014), 195-202.
%Y Cf. A060138, A060142.
%A _Clark Kimberling_, Mar 05 2001