#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define endl '\n'
const ll maxn = 1e5 + 5;
ll n;
ll a[maxn];
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	ll T;
	cin >> T;
	while (T--) {
		cin >> n;
		ll ans = 0;
		map<ll, vector<ll>>is;
		for (ll i = 1; i <= n; i++) {
			cin >> a[i];
			is[a[i] - i].push_back(a[i]);
		}
		for (auto& it : is) {
			auto& v = it.second;
			sort(v.begin(), v.end());
			for (ll i = v.size() - 1; i - 1 >= 0; i-=2) {
				ll t = v[i] + v[i - 1];
				if(t > 0)ans += t;
			}
		}
		cout << ans << endl;
	}
}