[seqfan] Erase my twins, I'll be back

[Éric Angelini]

Hello SeqFans,
erase two successive terms when they are the same.
The non-erased terms rebuild the starting sequence:
1,1,2,2,1,2,2,1,2,1,1,2,1,2,1,1,2,1,2,1,1,2,1,2,1,2,2,1,2,1,2,1,2,
2,1,2,1,2,1,2,1,1,2,1,2,1,2,1,2,1,1,2,1,2,1,2,1,2,1,...
This is easy to build by hand -- and boring: is there a 
simple morphism that could do the job?
(The "lexicographically first" question is impossible 
to solve here, I guess -- as one can always begin the
sequence with a bunch of 1s. Or insert a pair of 1s
at some point to "beat" the previous seq). I just wanted to show this example -- a "fractal with an
eraser" -- which might not enter the OEIS, no problemo!
Best,
É.


à+
É.
Catapulté de mon aPhone