login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A291800 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 first word we see in the orbit of that word 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. 1
0, 5, 0, 6, 15, 15, 0, 0, 0, 15, 15, 15, 15, 15, 0, 15, 0, 15, 15, 12, 15, 15, 15, 15, 19, 19, 13, 15, 0, 19, 0, 15, 15, 13, 0, 0, 15, 15, 15, 0, 0, 0, 13, 0, 19, 19, 13, 14, 0, 19, 19, 0, 17, 0, 13, 19, 0, 17, 19, 19, 31, 0, 0, 0, 15, 13, 13, 19, 13, 19, 0 (list; graph; refs; listen; history; text; internal format)
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 A291794 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, A291797.

Sequence in context: A200419 A271522 A069206 * A091685 A062824 A292904

Adjacent sequences:  A291797 A291798 A291799 * A291801 A291802 A291803

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Sep 04 2017

EXTENSIONS

a(31)-a(71) from Lars Blomberg, Sep 08 2017

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 21 07:23 EDT 2019. Contains 325192 sequences. (Running on oeis4.)