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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. 1
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, 22, 14, 16, 56, 22, 15, 16, 16, 15, 15, 15, 16, 16, 16, 15, 15, 56, 16, 56, 22, 22, 16, 16, 56, 22, 22, 56, 20, 56, 17, 22, 18, 20, 22, 22, 34, 56, 18, 18, 18, 18, 18 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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 A291795 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, A291795, A291797.

Sequence in context: A161645 A081289 A160504 * A227501 A294981 A079093

Adjacent sequences:  A291798 A291799 A291800 * A291802 A291803 A291804

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Sep 04 2017

EXTENSIONS

a(31)-a(67) from Lars Blomberg, Sep 08 2017

STATUS

approved

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Last modified August 2 09:22 EDT 2021. Contains 346422 sequences. (Running on oeis4.)