#include<bits/stdc++.h>
using namespace std;
const int INF=0x3f3f3f3f;
#define endl '\n'
#define x first
#define y second
typedef long long ll;
typedef pair<int,int> PII;
bool cmp(int a,int b)
{
	return a>b;
}
void solve()
{
	map<int,vector<int>> mp;
	ll n,ans=0;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		int x;
		cin>>x;
		mp[i-x].push_back(x);
	}
	for(auto &it : mp)
	{
		sort(it.y.begin(),it.y.end(),cmp);
		for(int i=0;i<it.y.size();i+=2)
		{
			if(i+1>=it.y.size())break;
			if(it.y[i]+it.y[i+1]>0)ans+=it.y[i]+it.y[i+1];
		}
	}
	cout<<ans<<endl;
}
int main()
{
	ios::sync_with_stdio(false);
	ios::sync_with_stdio(0);cin.tie(0),cout.tie(0);
	int t;
	cin>>t;
	while(t--)
	{
		solve();
	}
	return 0;
}