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Fixed point of the morphism 0->11, 1->1001.
3

%I #7 Jul 19 2022 14:58:52

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

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

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

%N Fixed point of the morphism 0->11, 1->1001.

%H Clark Kimberling, <a href="/A285621/b285621.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Fi#FIXEDPOINTS">Index entries for sequences that are fixed points of mappings</a>

%e 0 -> 11 -> 10011001 -> 100111111001100111111001 -> 10011111100110011001100110011001... ->

%t s = Nest[Flatten[# /. {0 -> {1, 1}, 1 -> {1, 0, 0, 1}}] &, {0}, 10] (* A285621 *)

%t Flatten[Position[s, 0]] (* A285622 *)

%t Flatten[Position[s, 1]] (* A285623 *)

%t SubstitutionSystem[{0->{1,1},1->{1,0,0,1}},{1},{5}][[1]] (* _Harvey P. Dale_, Jul 19 2022 *)

%Y Cf. A285622, A285623, A285625.

%K nonn,easy

%O 1

%A _Clark Kimberling_, May 01 2017