This is about an Merge Sort computer algorithm.

Firstly here's the full thing.

couldn't figure out how to get log as an exponent

I asked a question about this before and got a good answer that made me realise that what was going on was recursion. Now, to my understanding all recusion needs a base case. In this instance I'm thinking that this would be T(1) as this would mean that there would be no sorting to do. Does this mean that T(1) = 1? as in the last 3rd to last part where 2 to the log on n X T(n / 2 to the log of n) is reduced to n?

Also for each level of recursion that you go down I can understand that you would have another 2n - 1 (where n is the reduced input) but I'm having a hard time trying to see how this works as giving the 2n - 2 to log n -1 ... .

And lastly, and I'm quite sure this is linked to the above question, where does the + 1 come from in the last two but one parts?

Thanks.