cp's OEIS Frontend

A291798 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) = preperiod (or threshold) of orbit of that word.

%I A291798 #12 Sep 08 2017 16:13:14
%S A291798 3,4,6,2,17,15,9,11,13,14,16,12,24,10,12,19,14,23,21,4,13,9,25,11,29,
%T A291798 27,3,7,420,25,15,24,28,6,17,19,28,4,26,21,23,419,6,417,46,24,8,5,421,
%U A291798 26,28,415,12,413,10,44,27,10,40,22,84,411,18,20,29,9,11
%N A291798 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) = preperiod (or threshold) of orbit of that word.
%C A291798 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 A291798 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 A291798 This is an analog of A284119 for the words in A291797.
%H A291798 Lars Blomberg, <a href="/A291798/b291798.txt">Table of n, a(n) for n = 1..8190</a> (For terms in A291797 up to length 36.)
%H A291798 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 A291798 Cf. A284116, A284119, A291797.
%K A291798 nonn
%O A291798 1,1
%A A291798 _N. J. A. Sloane_, Sep 04 2017
%E A291798 a(31)-a(67) from _Lars Blomberg_, Sep 08 2017