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%I #9 Oct 07 2020 08:01:58
%S 1,4,6,8,9,12,13,16,18,20,21,24,25,28,30,31,34,36,38,39,42,43,46,48,
%T 49,52,54,56,57,60,61,64,66,67,70,72,73,76,78,80,81,84,85,88,90,92,93,
%U 96,97,100,102,103,106,108,109,112,114,116,117,120,121,124
%N Positions of 0 in A285255; complement of A285257.
%C Conjecture: 2n - a(n) is in {0,1} for n>=1.
%C See the comments of A285250 for a proof of this conjecture. - _Michel Dekking_, Oct 07 2020
%H Clark Kimberling, <a href="/A285256/b285256.txt">Table of n, a(n) for n = 1..10000</a>
%e As a word, A285255 = 011010..., in which 0 is in positions 1,4,6,8,9,...
%t s = Nest[Flatten[# /. {0 -> {1, 0}, 1 -> {0, 1, 1, 0}}] &, {0}, 12]; (* A285255 *)
%t Flatten[Position[s, 0]]; (* A285256 *)
%t Flatten[Position[s, 1]]; (* A285257 *)
%Y Cf. A285250, A285255, A285257, A285258.
%K nonn,easy
%O 1,2
%A _Clark Kimberling_, Apr 23 2017