#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define endl "\n"
#define ALL(x) (x).begin(), (x).end()
void solve()
{
    int n;
    cin >> n;
    vector<int> a(n + 1);
    map<int, vector<int>> g;
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
        a[i] -= i;
        g[a[i]].push_back(a[i] + i);
    }
    ll ans = 0;
    for (auto [x, adj] : g)
    {
        sort(ALL(adj), greater<int>());
        if (adj.size() == 1)
        {
            continue;
        }
        if (adj.size() == 2)
        {
            ans += max(0, adj[0] + adj[1]);
            continue;
        }
        for (int i = 0; i + 1 < adj.size(); i++)
        {
            if (adj[i + 1] > 0)
            {
                ans += adj[i] + adj[i + 1];
                i++;
            }
            else
            {
                if (a[i] + adj.back() > 0)
                {
                    ans += a[i] + adj.back();
                    break;
                }
            }
        }
    }
    cout << ans << "\n";
}
int main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int t;
    cin >> t;
    while (t--)
    {
        solve();
    }
}