[seqfan] Fractals with digit counts (odd or even)

[Eric Angelini]

Hello SeqFans,
if we look at chunks of _digits_ (odd or even) we will get two new (tricky)
sequences that are fractal, yes, but no permutation of the even or odd
numbers. We have always extended U and V with the smallest available integer
not yet present; the "separator" between two digit-chunks is always a single
digit (of the parity opposed to the parity of the chunk):

[odd-digit-chunks]:
U =  0,1,2,3,5,4,7,9,16,11,13,18,15,17,6,19,31,33,10,35,37,39,51,12,...
    0  1    2      3       5       4         7             9

[even-digit-chunks]:
V = 1,2,3,4,6,5,8,20,7,22,24,9,26,28,40,10,42,44,12,46,48,60,61,...
      1    2     3       4         6        5           8

Example of a number that will never belong to U: 212
Example of a number that will never belong to V: 101

Best,
É.