cp's OEIS Frontend

A291801 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.

%I A291801 #11 Sep 08 2017 16:09:17
%S A291801 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 A291801 22,14,16,56,22,15,16,16,15,15,15,16,16,16,15,15,56,16,56,22,22,16,16,
%U A291801 56,22,22,56,20,56,17,22,18,20,22,22,34,56,18,18,18,18,18
%N A291801 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 A291801 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 A291801 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 A291801 This is an analog of A291795 for the words in A291797.
%H A291801 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 A291801 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 A291801 Cf. A284116, A291794, A291795, A291797.
%K A291801 nonn
%O A291801 1,1
%A A291801 _N. J. A. Sloane_, Sep 04 2017
%E A291801 a(31)-a(67) from _Lars Blomberg_, Sep 08 2017