Weekend Challenge Sharpened: Missing Positions in Champernowne's Constant

[nlj]

The following is weird (and wonderful):

Code:

ch  min_c   max_c    i(max_c)
0   0       0        (9)
1   1       90       189
2   91      1890     2889
3   1891    28890    38889
4   28891   388890   488889
5   388891  4888890  5888889
...
13  118888888888891  1288888888888890  1388888888888889
...

Where I break Champernowne's Number into "levels", where ch is the characteristic of the logarithm of the integers at a given level (i.e. integers 1 to 9 at the level with ch = 0; 10 to 99 for ch = 1 etc.) and min_c is the number of the smallest "missing position" at that level, max_c is the largest "missing position" at that level and i(max_c) is the index into Champernowne's Number of max_c.

I believe this observation will permit me to eliminate iteration from my solution. But I'm still working on that bit...