Pb with clash of code calcul pts?

with my rank (around 110) I supposed ti gain: 5000^((5000 - 110 + 1) / 5000) = 4153pts… why I have only 2550 ??

Not everyone on the clash of code leaderboard is considered active (probably after not clashing for a certain time). Only active users are taken into account, thus the maximum points available is about 3300 (the number of active players).
3300^((3300-110+1)/3300) = 2525, which is quite close to the points you have.