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.

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

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