2176. Count Equal and Divisible Pairs in an Array

class Solution:
    def countPairs(self, nums: List[int], k: int) -> int:
        n = len(nums)
        return sum(
            nums[i] == nums[j] and (i * j) % k == 0
            for i in range(n)
            for j in range(i + 1, n)
        )