login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A287234
0-limiting word of the morphism 0->01, 1->20, 2->1, with initial term 1.
5
1, 0, 1, 0, 1, 2, 0, 1, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 0, 0, 1, 2, 0, 1, 0, 1, 0, 1, 2, 0, 1, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 0, 0, 1, 2, 0, 1, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 2, 0, 1, 0, 1, 2, 0, 0, 1, 2, 0, 1, 0, 1, 0, 1, 2, 0, 1, 0, 1, 0
OFFSET
1,6
COMMENTS
Starting with 0, the first 5 iterations of the morphism yield words shown here:
1st: 20
2nd: 101
3rd: 200120
4th: 1010120101
5th: 2001200120101200120
The 0-limiting word is the limit of the words for which the number of iterations is even.
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 = 2.246979603717467061050009768008...,
V = 2.801937735804838252472204639014...,
W = 5.048917339522305313522214407023...
If n >=2, then u(n) - u(n-1) is in {1,2,3}, v(n) - v(n-1) is in {2,3,4}, and w(n) - w(n-1) is in {4,5,7}.
LINKS
EXAMPLE
2nd iterate: 101
4th iterate: 1010120101
6th iterate: 101012010101201012001201010120101
MATHEMATICA
s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {2, 0}, 2 -> 1}] &, {1}, 10] (* A287234 *)
Flatten[Position[s, 0]] (* A287235 *)
Flatten[Position[s, 1]] (* A287236 *)
Flatten[Position[s, 2]] (* A287237 *)
CROSSREFS
Cf. A287002 (initial 0 instead of 1), A287235, A287236, A287237, A287240 (1-limiting word).
Sequence in context: A364389 A116927 A137276 * A309938 A140581 A137277
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, May 23 2017
STATUS
approved