//ADGIL

//-- Chivalrous
#include<bits/stdc++.h>
// #pragma GCC optimize("Ofast,no-stack-protector", 3)
#define endl '\n'
#define int long long
#define NO cout << "NO" << endl
#define YES cout << "YES" << endl
#define No cout << "No" << endl
#define Yes cout << "Yes" << endl
#define PII pair<int,int> 
#define PIII pair<pair<int,int> , int>
#define x first
#define y second
#define pb push_back
#define IOS ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr)
#define SOLVE int T;cin >> T;while(T--) SV()
#define in insert
using namespace std;
int gcd(int a, int b) {if (b == 0) {return a;}return gcd(b, a % b);}
int lcm(int a, int b) {return a * b / gcd(a, b);}
int ksm(int a, int b, int p) {int res = 1;while(b){if(b & 1)res = res * a % p;b >>= 1;a = a * a % p;}return res;}
bool is_prime(int x){if(x < 2) return false; if(x == 2)return true;for(int i = 2; i * i <= x; i ++) if(x % i == 0)return false;return true;}
//ksm(a , p - 2, p);!(a % p) -> ok;
const int N = 100010;

void SV() {

	unordered_map<int,int> mp;
	int n;
	cin >> n;

	vector<int> a(n + 10);
	vector<int> e[N];

	for(int i = 1; i <= n; i ++) cin >> a[i];
	int idx = 0;
	
	for(int i = 1; i <= n; i ++) {
	   // cout << i - a[i] << endl;
		if(!mp[i - a[i]]) {
			mp[i - a[i]] = ++idx;
			e[idx].push_back(a[i]);
// 			cout << 1 << endl;
		}
		else {
			e[mp[i - a[i]]].push_back(a[i]);
		}
	}

	for(int i = 1; i <= idx; i ++) sort(e[i].begin() , e[i].end() , greater<int>());

	int ans = 0;
	for(int i = 1; i <= idx; i ++) {
	    int m = e[i].size();
	    for(int j = 0; j + 1 < m; j += 2) {
	        int res = e[i][j] + e[i][j + 1];
	        if(res < 0) break;
	        else ans += res;
	    }
	}
	cout << ans << endl;
}

signed main(){IOS;SOLVE;}

/*
                  _ooOoo_
                  o8888888o
                  88" . "88
                  (| ^_^ |)
                  O\  =  /O
               ____/`---'\____
             .'  \\|     |//  `.
            /  \\|||  :  |||//  \
           /  _||||| -:- |||||-  \
           |   | \\\  -  /// |   |
           | \_|  ''\---/''  |   |
           \  .-\__  `-`  ___/-. /
         ___`. .'  /--.--\  `. . __
      ."" '<  `.___\_<|>_/___.'  >'"".
     | | :  `- \`.;`\ _ /`;.`/ - ` : | |
     \  \ `-.   \_ __\ /__ _/   .-` /  /
======`-.____`-.___\_____/___.-`____.-'======
                   `=---='
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
         佛祖保佑AC，永无bug缠身
*/