> I've been trying to solve this problem and i've checked my answers with a brute force program, but still i receive wrong answer. Could some one help me?
> Are these answers corect?
> f(4, 307) = 14029918686276756
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~14029918686276757
> f(4, 500) = 424587590915884800
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~424587590915884825
> f(3, 1000) = 133667000166700
> f(2, 5000) = 41679167500