A291794 Consider Post's tag system applied to the word (100)^n; a(n) = length of first word we see 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.

5, 15, 15, 19, 0, 31, 85, 37, 31, 37, 55, 37, 0, 0, 91, 85, 31, 127, 31, 33, 37, 0, 37, 37, 0, 73, 73, 163, 55, 19, 73, 157, 37, 73, 37, 37, 37, 163, 55, 37, 163, 37, 37, 85, 37, 0, 0, 85, 37, 127, 91, 37, 37, 0, 37, 69, 19, 31, 163, 163, 87, 55, 0, 37, 0, 55

Offset: 1

Author

N. J. A. Sloane, Sep 04 2017

Keywords

• nonn

Links

• Lars Blomberg, Table of n, a(n) for n = 1..6075
• Peter R. J. Asveld, On a Post's System of Tag. Bulletin of the EATCS 36 (1988), 96-102.

Crossrefs

Cf. A284116 and the cross-references there.

Extensions

a(33) and beyond from Lars Blomberg, Apr 19 2018