#include <bits/stdc++.h>
#define int long long
#define inf 0x3f3f3f3f
#define ll long long
#define pii pair<int, int>
#define tii tuple<int, int, int>
#define db double
#define all(a) a.begin(), a.end()
using namespace std;
const int maxn = 1e5 + 10;
const int mod = 998244353;
int arr[maxn];
bool cmp(int i, int j) {
    return arr[i] > arr[j];
}
void solve() {
    int n; cin >> n;
    map<int, vector<int>> mp;
    for (int i = 1; i <= n; i++) {
        cin >> arr[i];
        mp[i - arr[i]].push_back(i);
    }
    int ans = 0;
    for (auto [_, vec] : mp) {
        sort(all(vec), cmp);
        for (int i = 0; i < vec.size() - 1; i += 2) {
            int tem = arr[vec[i]] + arr[vec[i + 1]];
            if (tem > 0) ans += tem;
            else break;
        }
    }
    cout << ans << "\n";
}
signed main() {
    // freopen("1.in", "r", stdin);
    // freopen("1.out", "w", stdout);
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int t = 1;
    cin >> t;
    while (t--)
        solve();
    return 0;
}