2652. Sum Multiples 

1
2
3
4
5
6
7
8
9
10
11
12
13
class Solution {
    public int sumOfMultiples(int n) {
        int sum = 0;
        
        for (int i = 1; i <= n; i++) {
            if (i % 3 == 0 || i % 5 == 0 || i % 7 == 0) {
                sum += i;
            }
        }

        return sum;
    }
}

References

2652. Sum Multiples