codeforces#P1520D. Same Differences

Same Differences

Description

You are given an array aa of nn integers. Count the number of pairs of indices (i,j)(i, j) such that i<ji < j and ajai=jia_j - a_i = j - i.

The first line contains one integer tt (1t1041 \le t \le 10^4). Then tt test cases follow.

The first line of each test case contains one integer nn (1n21051 \le n \le 2 \cdot 10^5).

The second line of each test case contains nn integers a1,a2,,ana_1, a_2, \ldots, a_n (1ain1 \le a_i \le n) — array aa.

It is guaranteed that the sum of nn over all test cases does not exceed 21052 \cdot 10^5.

For each test case output the number of pairs of indices (i,j)(i, j) such that i<ji < j and ajai=jia_j - a_i = j - i.

Input

The first line contains one integer tt (1t1041 \le t \le 10^4). Then tt test cases follow.

The first line of each test case contains one integer nn (1n21051 \le n \le 2 \cdot 10^5).

The second line of each test case contains nn integers a1,a2,,ana_1, a_2, \ldots, a_n (1ain1 \le a_i \le n) — array aa.

It is guaranteed that the sum of nn over all test cases does not exceed 21052 \cdot 10^5.

Output

For each test case output the number of pairs of indices (i,j)(i, j) such that i<ji < j and ajai=jia_j - a_i = j - i.

Samples

输入数据 1

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

输出数据 1

1
3
3
10