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Take n-th word over {1,2} listed in A291797 and apply the Post tag system described in A284116 (but adapted to the alphabet {1,2}); a(n) = length of the longest word in the orbit, or -1 if the orbit is unbounded.
2

%I #11 Sep 08 2017 16:09:17

%S 3,6,6,6,16,16,9,9,9,16,16,16,16,16,12,16,12,16,16,12,16,16,16,16,22,

%T 22,14,16,56,22,15,16,16,15,15,15,16,16,16,15,15,56,16,56,22,22,16,16,

%U 56,22,22,56,20,56,17,22,18,20,22,22,34,56,18,18,18,18,18

%N Take n-th word over {1,2} listed in A291797 and apply the Post tag system described in A284116 (but adapted to the alphabet {1,2}); a(n) = length of the longest word in the orbit, or -1 if the orbit is unbounded.

%C Post's tag system maps a word w over {1,2} to w', where if w begins with 1, w' is obtained by appending 11 to w and deleting the first three letters, or if w begins with 2, w' is obtained by appending 2212 to w and deleting the first three letters.

%C We work over {1,2} rather than the official alphabet {0,1} because of the prohibition in the OEIS of terms (other than 0 itself) which begin with 0.

%C This is an analog of A291795 for the words in A291797.

%H Lars Blomberg, <a href="/A291801/b291801.txt">Table of n, a(n) for n = 1..8190</a> (For terms in A291797 up to length 36.)

%H Peter R. J. Asveld, <a href="http://doc.utwente.nl/66184/1/1988m20.pdf">On a Post's System of Tag</a>. Bulletin of the EATCS 36 (1988), 96-102. See Table 3.

%Y Cf. A284116, A291794, A291795, A291797.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Sep 04 2017

%E a(31)-a(67) from _Lars Blomberg_, Sep 08 2017