Beautiful Pairs

You are given an array a of n integers. A pair of indices i,j is beautiful if j - i = a_j - a_i, where j > i. You have to count the number of beautiful pairs of indices in the array.

Input Format

• The first line contains an integer t denoting the number of testcases.
• The first line of each testcase contains an integer n denoting the number of elements in the array a.
• The second line of the each test case contains n integers - array a.
• Sum of n all over test cases does not exceed 2x10⁵.

Output Format

For each test case output the number of beatiful pairs of indices in the array.

Constraints

• 1 \(\leq\) t \(\leq\) 10⁴
• 1 \(\leq\) n \(\leq\) 2x10⁵
• 1 \(\leq\) a_i \(\leq\) n

Sample Input 0

4
6
3 5 1 4 6 6
3
1 2 3
4
1 3 3 4
6
1 6 3 4 5 6

Sample Output 0

1
3
3
10