Description: You are given an array $$$a$$$ of $$$n$$$ integers. Count the number of pairs of indices $$$(i, j)$$$ such that $$$i < j$$$ and $$$a_j - a_i = j - i$$$. Input Format: The first line contains one integer $$$t$$$ ($$$1 \le t \le 10^4$$$). Then $$$t$$$ test cases follow. The first line of each test case contains one integer $$$n$$$ ($$$1 \le n \le 2 \cdot 10^5$$$). The second line of each test case contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ ($$$1 \le a_i \le n$$$) — array $$$a$$$. It is guaranteed that the sum of $$$n$$$ over all test cases does not exceed $$$2 \cdot 10^5$$$. Output Format: For each test case output the number of pairs of indices $$$(i, j)$$$ such that $$$i < j$$$ and $$$a_j - a_i = j - i$$$. Note: None