Calculate Money in Leetcode Bank

Input: n = 4

Output: 10

After the 4th day, the total is 1 + 2 + 3 + 4 = 10.

Input: n = 10

Output: 37

After the 10th day, the total is (1 + 2 + 3 + 4 + 5 + 6 + 7) + (2 + 3 + 4) = 37. Notice that on the 2nd Monday, Hercy only puts in $2.

Input: n = 20

Output: 96

After the 20th day, the total is (1 + 2 + 3 + 4 + 5 + 6 + 7) + (2 + 3 + 4 + 5 + 6 + 7 + 8) + (3 + 4 + 5 + 6 + 7 + 8) = 96.

Problem