0, 1, 10...
1, 2, 3, 5...
Now I see where you get your math from Q. :p
That's a windows problem I believe. If you get a lot of files numbered, say, from 1 to 35 and get windows to arrange it in alphabetical order, it will work like this too (if I am not mistaken)
1, 10, 11 ... 19, 2...