staving Alex Fink:

> Anyway, there are conceivable base-type systems where it's worse.  For
> example (I think), consider the base-3 system where the digits are 0, 1, and
> -7, which I'll denote s.  Counting then runs
> 0, 1, 10s, 10, 11, 11s, 10s0, 10s1, 11ss, 100, 101, 10s0s, 110, 111, 10s1s,
> 11s0, 11s1, 11sss, 10s00, 10s01, 100s, 10s10, 10s11, 101s, 11ss0, 11ss1,
> 10s0ss, 1000, ...
>

I used to play around with a base 1+i counting system at one point. 
Digits could be 0, 1 or i

Base i+1	Decimal
0		0
1		1
i		i
10		1+i
11		2+i
1i		1+2i
i0		i-1
i1		i
ii		2i-1
100		-2
101		-1
10i		-2+1
110		i-1
111		i
11i		2i-1
1i0		i-3
1i1		i-2
1ii		2i-3
i00		-2i
i01		1-2i
i0i		-i
i10		1-i
i11		2-i
i1i		1
ii0		i-3
ii1		i-2
iii		2i-3

This base is mainly of interest to particularly insane mathematicians.
Pete