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A287086
Start with 0 and repeatedly substitute 0->01, 1->22, 2->0.
4
0, 1, 2, 2, 0, 0, 0, 1, 0, 1, 0, 1, 2, 2, 0, 1, 2, 2, 0, 1, 2, 2, 0, 0, 0, 1, 2, 2, 0, 0, 0, 1, 2, 2, 0, 0, 0, 1, 0, 1, 0, 1, 2, 2, 0, 0, 0, 1, 0, 1, 0, 1, 2, 2, 0, 0, 0, 1, 0, 1, 0, 1, 2, 2, 0, 1, 2, 2, 0, 1, 2, 2, 0, 0, 0, 1, 0, 1, 0, 1, 2, 2, 0, 1, 2, 2
OFFSET
1,3
COMMENTS
The fixed point of the morphism 0->01, 1->20, 2->1. Let u be the sequence of positions of 0, and likewise, v for 1 and w for 2. Let U, V, W be the limits of u(n)/n, v(n)/n, w(n)/n, respectively. Then 1/U + 1/V + 1/W = 1, where
U = 2.28537528186132044169516884721360670506...,
V = 3.87512979416277882597397059430967806752...,
W = 3.28537528186132044169516884721360670506...
If n >=2, then u(n) - u(n-1) is in {1,2,4}, v(n) - v(n-1) is in {2,4,6}, and w(n) - w(n-1) is in {1,3,5,9}.
MATHEMATICA
s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {2, 2}, 2 -> 0}] &, {0}, 10] (* A287086 *)
Flatten[Position[s, 0]] (* A287087 *)
Flatten[Position[s, 1]] (* A287088 *)
Flatten[Position[s, 2]] (* A287089 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, May 21 2017
STATUS
approved