Hello.

Recently, I was solving a problem to which I simplified it to evaluating this summation:

C is n choose k. N is up to 1000, and K is up to 2^30.

Answer appears to be I guess {*K* * (*N* - 1)^{K}}

I can't get however how to arrive at this, or perhaps compute the original summation in a smart way, I tried messing expanding nCk to factorials, but didn't get anywhere. <.<