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%I #22 Sep 21 2018 08:47:03
%S 0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,1,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,2,0,1,
%T 0,2,0,1,0,3,0,1,0,2,0,1,0,1,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,3,0,1,0,2,
%U 0,1,0,3,0,1,0,2,0,1,0,1,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,2,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,1,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,1,0,1,0,2
%N Fixed point of the morphism 0 -> 01, 1 -> 02, 2 -> 03, 3 -> 01.
%C See A191250.
%F a(n) = 0 for odd n; a(n) == A007814(n) (mod 3) for even n. - _Jianing Song_, Sep 21 2018
%t t = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {0, 2}, 2 -> {0, 3}, 3 -> {0, 1}}] &, {0}, 9] (* A191255 *)
%t Flatten[Position[t, 0]] (* A005408, the odds *)
%t a = Flatten[Position[t, 1]] (* A067368 *)
%t b = Flatten[Position[t, 2]] (* A213258 *)
%t a/2 (* A191257 *)
%t b/4 (* a/2 *)
%Y Cf. A191250.
%Y Positions of 0 or 3: A191257; positions of 1: A067368; positions of 2: A213258.
%K nonn
%O 1,4
%A _Clark Kimberling_, May 28 2011
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