#include <bits/stdc++.h>
// #include <bits/extc++.h>
// using namespace __gnu_pbds;
// gp_hash_table<int, bool> hs;
#define bit1(x) __builtin_popcount(x)
#define all(x) (x).begin(), (x).end()
#define lowbit(i) ((i) & -(i))
#define ull unsigned long long
#define int long long
// #define ll long long
#define Genshin return
#define Impact 0
#define endl '\n'
using namespace std;
const int mod = 998244353;
const int N = 2e5 + 10;
int ksm(int base, int n)
{
    int res = 1;
    while (n > 0)
    {
        if (n & 1)
            res = (res * base) % mod;
        base = (base * base) % mod;
        n >>= 1;
    }
    return res;
}

void solve()
{
    int n;
    cin >> n;
    vector<int> a(n + 1);
    map<int, vector<int>> m;
    int ans = 0;
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
        m[a[i] - i].push_back(a[i]);
    }
    for (auto [_, x] : m)
    {
        sort(all(x));
        for (int i = x.size() - 1; i - 1 >= 0; i -= 2)
        {
            if (x[i] + x[i - 1] < 0)
                break;
            ans += x[i] + x[i - 1];
        }
    }
    cout << ans << endl;
    return;
}
signed main()
{
    ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
    int tt = 1;
    cin >> tt;
    while (tt--)
    {
        solve();
    }
    Genshin Impact;
}