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Fixed point of the morphism 0 -> 001, 1 -> 02, 2 -> 01.
4

%I #10 Aug 25 2019 10:18:33

%S 0,0,1,0,0,1,0,2,0,0,1,0,0,1,0,2,0,0,1,0,1,0,0,1,0,0,1,0,2,0,0,1,0,0,

%T 1,0,2,0,0,1,0,1,0,0,1,0,0,1,0,2,0,0,1,0,2,0,0,1,0,0,1,0,2,0,0,1,0,0,

%U 1,0,2,0,0,1,0,1,0,0,1,0,0,1,0,2,0,0,1,0,0,1,0,2,0,0,1,0,1,0,0,1,0,0,1,0,2,0,0,1,0,2,0,0,1,0,0,1,0,2,0,0,1,0,0,1,0,2,0,0,1,0,1,0

%N Fixed point of the morphism 0 -> 001, 1 -> 02, 2 -> 01.

%C See A191250.

%C Proof of Kimberling's conjecture on the positions of 0 in this sequence: consider the letter to letter projection pi given by pi(0) = 0, pi(1) = 1, pi(2) = 1. Then pi sigma = tau pi, where tau is the morphism on {0,1} given by tau(0) = 001, tau(1) = 01. It follows that pi(a) = x, where x = A188432 is the fixed point of tau. Note that the positions of zero in a = A191269 are equal to the positions of zero in x. Since x is the infinite Fibonacci word with a zero in front, it follows that these positions are given by A026351. - _Michel Dekking_, Aug 24 2019

%t t = Nest[Flatten[# /. {0 -> {0, 0, 1}, 1 -> {0, 2}, 2 -> {0, 1}}] &, {0}, 7] (* A191269 *)

%t Flatten[Position[t, 0]] (* A026351, 1+lower Wythoff sequence, conjectured *)

%t Flatten[Position[t, 1]] (* A191270 *)

%t Flatten[Position[t, 2]] (* A191271 *)

%Y Cf. A191250, A191270, A191271.

%K nonn

%O 1,8

%A _Clark Kimberling_, May 28 2011