#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pii;


void solve() {
	int n;
	cin >> n;
	vector<ll> a(n), b(n);
	map<ll, vector<ll>> mpv;
	for (int i = 0; i < n; i ++) {
		cin >> a[i];
		mpv[a[i] - i].push_back(a[i]);
	}
	ll ans = 0;
	for (auto [x, v] : mpv) {
		if (v.size() < 2) continue;
		sort(v.begin(), v.end(), greater<ll>());
		for (int i = 1; i < v.size(); i += 2) {
			if (v[i] + v[i - 1] > 0) {
				ans = ans + v[i] + v[i - 1];
			}
		}
	}

	cout << ans << '\n';

}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr); cout.tie(nullptr);
	int t = 1;
	cin >> t;
	while (t --) {
		solve();
	}
}