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%I #4 May 29 2017 23:58:47
%S 3,4,8,11,15,16,21,23,25,30,32,34,39,40,44,47,51,52,57,58,62,66,68,70,
%T 74,78,79,84,85,89,93,95,97,101,105,106,111,112,116,119,123,124,129,
%U 131,133,138,140,142,147,148,152,155,159,160,165,166,170,173,177
%N Positions of 2 in A287443.
%C a(n) - a(n-1) is in {1, 2, 3, 4, 5} for n >= 1; also, 3n - a(n) is in {0, 1, 2} for n >= 1. The first 20 numbers 3n - a(n) are 0, 2, 1, 1, 0, 2, 0, 1, 2, 0, 1, 2, 0, 2, 1, 1, 0, 2, 0, 2, with 0 in positions given by A287444.
%H Clark Kimberling, <a href="/A287446/b287446.txt">Table of n, a(n) for n = 1..10000</a>
%t s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{2, 0, 1}, 2->{0, 2, 1}}] &, {0}, 9]; (*A287443*)
%t Flatten[Position[s, 0]]; (*A287444*)
%t Flatten[Position[s, 1]]; (*A287445*)
%t Flatten[Position[s, 2]]; (*A287446*)
%Y Cf. A287443, A287444, A287445.
%K nonn,easy
%O 1,1
%A _Clark Kimberling_, May 26 2017