# [seqfan] Cut the sequence after it's odd/even digits

Eric Angelini Eric.Angelini at kntv.be
Tue Oct 29 12:25:01 CET 2013

```Hello again SeqFans (last post of the day, sorry);
More self-describing sequences with a knife...

Cut the sequence C(odd) after every odd digit.
The digit-size of each chunk is given by C(odd) itself.
C(odd) was always extended with the smallest integer not
C(odd) is thus the lexicographically first sequence of
this kind:

C(odd)=
1,2,3,4,6,5,8,22,7,24,26,21,28,40,12,42,44,46,14,48,60,62,64,66,68,80,82,84,86,16,...

The first chunks of C(odd) are visible here (a star is a cut):

1*,2,3*,4,6,5*,8,22,7*,24,26,21*,28,40,1*2,42,44,46,1*4,48,60,62,64,66,68,80,82,84,86,1*6,...
1   2     3      4        6         5          7                  22

C(even) can be build with the same idea:

C(even)=
3,1,2,4,5,6,7,9,10,11,13,8,15,17,12,19,31,33,21,35,37,39,14,51,53,55,57,16,...

Digit-chunks:

3,1,2*,4*,5,6*,7,9,10*,11,13,8*,15,17,12*,19,31,33,2*1,35,37,39,14*,51,53,55,57,16*,...
3    1   2      4       5         6         7            9            10

Best,
É.

```