Yes, I figured it out in a brief moment after I posted this.

The case is realy unnecessary, since when n=1, the expression still holds.

This is not clever, it's hardcoded.

So the compiler adds the value to the value? And that's faster than bitshifting? Huh, that's interesting.

It was faster at the beggining (like years ago) but now precesors are stronger and there is no point in doing it. You should not do it because it is easy to make mistakes and it is not clear enought.

Nice, but you could have been using Math.Max() and Math.Min(), it would save you like 8 lines of code (and no ugly if/else).

Awesome explanation. I can see that you had lots of fun :P