A291799 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) = period of orbit of that word, or 0 if the orbit ends at the empty word.

0, 2, 0, 2, 6, 6, 0, 0, 0, 6, 6, 6, 6, 6, 0, 6, 0, 6, 6, 2, 6, 6, 6, 6, 6, 6, 4, 6, 0, 6, 0, 6, 6, 4, 0, 0, 6, 6, 6, 0, 0, 0, 6, 0, 6, 6, 4, 6, 0, 6, 6, 0, 6, 0, 6, 6, 0, 6, 6, 6, 10, 0, 0, 0, 6, 6, 4, 6, 6, 6, 0, 4, 0, 0, 0, 6, 6, 6, 0, 6, 4, 6, 6, 2, 6, 6, 6

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 A291793 (or A284121) 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, A284121, A291793, A291797.

Sequence in context: A157491 A094385 A355260 * A295027 A225479 A156815

Adjacent sequences: A291796 A291797 A291798 * A291800 A291801 A291802

Keyword

nonn

Author

N. J. A. Sloane, Sep 04 2017

Extensions

a(31)-a(87) from Lars Blomberg, Sep 08 2017

Status

approved