1. EXP needed for level 1 = 0 2. EXP needed for next level = EXP needed for current level + (next level) * 1000

Therefore: level 1 - 0 level 2 - 2000 level 3 - 5000 level 4 - 9000 and so on. Therefore, the formula for the needed EXP for a level N should be:

EXP = ( (N-1)*(N+2)/2 ) * 1000

For large N, the formula gives slightly more than

EXP ~ (N*N/2)*1000

IIRC, right clicking on your score in your personal screen will pop up a message box, which will tell you: 1. For which level you qualify currently. 2. How many EXP you need for next level Therefore, computations aren't needed.