>
>Consider that there are 4,294,967,295 possible values (2 ^ 32 - 1)
>
>
>Are You sure ?
>Then with 1 bit you have 2^1 - 1 = 1.

I'm absolutely sure. What this is is a mathematical trick.

2 ^ 4 - 1 = 15 (0x0F)
2 ^ 3 - 1 = 7 (0x07)
2 ^ 2 - 1 = 3 (0x03)