#include <bits/stdc++.h>
using namespace std;
#define int long long

void solve() {
    int n;cin >> n;
    vector<int>a(n + 1);
    unordered_map<int, vector<int>>mp;
    for (int i = 1;i <= n;i++) {
        cin >> a[i];
        mp[a[i] - i].push_back(a[i]);
    }

    int ans = 0;
    for (auto [x, vec] : mp) {
        if (vec.size() < 1)continue;
        sort(vec.rbegin(), vec.rend());
        // cout << x << "\n";
        // for (auto xx : vec) {
            // cout << xx << " ";
        // }
        // cout << "\n";
        for (int i = 0;i + 1 < vec.size();i += 2) {
            // cout << i << "ii\n";
            ans += max(0LL, vec[i] + vec[i + 1]);
        }
    }
    cout << ans << "\n";

}

signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int T = 1;
#ifdef LOCAL
    freopen("data.in", "r", stdin);
    freopen("data.out", "w", stdout);
#endif
    cin >> T;
    while (T--)
        solve();
    return 0;
}