%I #4 May 24 2017 10:00:18
%S 4,8,11,13,17,21,24,26,30,33,35,37,40,42,46,50,53,55,59,63,66,68,72,
%T 75,77,79,82,84,88,92,95,97,101,104,106,108,111,113,115,118,120,124,
%U 127,129,131,134,136,140,144,147,149,153,157,160,162,166,169,171
%N Positions of 1 in A287240.
%H Clark Kimberling, <a href="/A287242/b287242.txt">Table of n, a(n) for n = 1..10000</a>
%t s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {2, 0}, 2 -> 1}] &, {1}, 11] (* A287240 *)
%t Flatten[Position[s, 0]] (* A287241 *)
%t Flatten[Position[s, 1]] (* A287242 *)
%t Flatten[Position[s, 2]] (* A287243 *)
%Y Cf. A287240, A287241, A287243.
%K nonn,easy
%O 1,1
%A _Clark Kimberling_, May 24 2017