A291802 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) = position of the longest word in the orbit, or -1 if the orbit is unbounded.

0, 3, 0, 0, 16, 14, 0, 0, 0, 13, 15, 11, 23, 9, 0, 18, 0, 22, 20, 0, 12, 8, 24, 10, 20, 18, 2, 6, 106, 16, 0, 23, 27, 0, 0, 0, 27, 5, 25, 0, 0, 105, 3, 103, 37, 15, 1, 1, 107, 17, 19, 101, 9, 99, 2, 35, 7, 7, 31, 13, 71, 97, 0, 0, 0, 0, 0, 22, 0, 34, 0, 0, 0

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 A291796 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, A291796, A291797.

Sequence in context: A338464 A278208 A105786 * A221828 A368348 A278188

Adjacent sequences: A291799 A291800 A291801 * A291803 A291804 A291805

Keyword

nonn

Author

N. J. A. Sloane, Sep 04 2017

Extensions

a(31)-a(73) from Lars Blomberg, Sep 08 2017

Status

approved