#include <iostream>
#include <algorithm>
#include <map>
#include <queue>
#define endl "\n"
#define int long long
using namespace std;
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0),cout.tie(0);
	int t;
	cin >> t;
	while(t--){
		int n,m=0;
		map<int,int> S; 
		cin >> n;
		priority_queue<int> heap[n+1];
		int now=0;
		for(int i=1;i<=n;i++){
			int x;
			cin >> x;
			if(S.count(x-now))
				heap[S[x-now]].push(x);
			else{
				S[x-now]=++m;
				heap[m].push(x);
			}
			now++;
		}
		int res=0;
		for(int i=1;i<=m;i++){
			while(heap[i].size()>1){
				int t1=heap[i].top();
				heap[i].pop();
				int t2=heap[i].top();
				heap[i].pop();
				if(t1+t2>=0) res+=t1+t2;
				else break;
			}
		}
		cout << res << endl;
	}
	return 0;
}