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 A291800 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 first word we see in the orbit of that word that is in the cycle, if the orbit cycles, or 0 if the orbit reaches the empty string, or -1 if the orbit is unbounded. 1
 0, 5, 0, 6, 15, 15, 0, 0, 0, 15, 15, 15, 15, 15, 0, 15, 0, 15, 15, 12, 15, 15, 15, 15, 19, 19, 13, 15, 0, 19, 0, 15, 15, 13, 0, 0, 15, 15, 15, 0, 0, 0, 13, 0, 19, 19, 13, 14, 0, 19, 19, 0, 17, 0, 13, 19, 0, 17, 19, 19, 31, 0, 0, 0, 15, 13, 13, 19, 13, 19, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS 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. 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. This is an analog of A291794 for the words in A291797. LINKS Lars Blomberg, Table of n, a(n) for n = 1..8190 (For terms in A291797 up to length 36.) Peter R. J. Asveld, On a Post's System of Tag. Bulletin of the EATCS 36 (1988), 96-102. See Table 3. CROSSREFS Cf. A284116, A291794, A291797. Sequence in context: A200419 A271522 A069206 * A091685 A062824 A292904 Adjacent sequences:  A291797 A291798 A291799 * A291801 A291802 A291803 KEYWORD nonn AUTHOR N. J. A. Sloane, Sep 04 2017 EXTENSIONS a(31)-a(71) from Lars Blomberg, Sep 08 2017 STATUS approved

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Last modified July 21 07:23 EDT 2019. Contains 325192 sequences. (Running on oeis4.)