#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
#define int long long

int a[N];

struct node 
{
    int val;
    int id;
}b[N];

bool cmp(node a, node b)
{
    if(b.val == a.val)
    {
        return a.id > b.id;
    }
    return a.val > b.val;
}

signed main()
{
    int T;
    cin >> T;
    while(T--)
    {
        int n;
        cin >> n;
        for (int i = 0; i < n; ++i)
        {
            cin >> a[i];
        }

        for(int i = 0; i < n; i ++)
        {
            b[i].id = i;
            b[i].val = a[i] - i;
        }

        sort(b, b + n, cmp);

        int ans = 0;
        for(int i = 0; i < n; i ++)
        {
            // cout << b[i].val << " " << b[i].id << endl;
            if(b[i].val == b[i + 1].val)
            {
                // cout <<"id"<< b[i].id << " " << b[i + 1].id << endl;
                ans += max((int)0, a[b[i].id] + a[b[i + 1].id]);
                i ++;
            }
        }
        cout << ans << endl;
    }
}