#include<bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int ,int> PII;
map<int,vector<int>> mp;
vector<int> key;

bool cmp(int a,int b){return a > b;}

void solve()
{
    mp.clear();key.clear();
    int n;cin>>n;
    for(int i = 1;i<=n;i++)
    {
        int a;cin>>a;
        int tmp = a - i;
        key.push_back(tmp);
        mp[tmp].push_back(a);
    }

    sort(key.begin(),key.end());
    key.erase(unique(key.begin(),key.end()),key.end());

    int ans = 0;
    for(int i = 0;i<key.size();i++)
    {
        sort(mp[key[i]].begin(),mp[key[i]].end(),cmp);
        int cnt = 0;
        for(int j = 0;j<mp[key[i]].size();j++)
        {
            if(mp[key[i]][j] >= 0) cnt ++;
            else break;
        }
        if(cnt % 2)
        {
            for(int j = 0;j<cnt-1;j++)
            {
                ans += mp[key[i]][j];
            } 
            int ans1 = 0;
            if(cnt + 1 <= mp[key[i]].size())
            {
                for(int j = 0;j<cnt+1;j++)
                {
                    ans1 += mp[key[i]][j];
                } 
                ans = max(ans,ans1);
            }
        }
        else 
        {
            for(int j = 0;j<cnt;j++)
            {
                ans += mp[key[i]][j];
            }
        }
     }
    ans = max(ans,0LL);
    cout<<ans<<endl;
    return ;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    int _;cin>>_;
    while(_--)
    {
        solve();
    }
    return 0;
}