#include<bits/stdc++.h>
#define ll long long
#define rep(i,l,r) for(int i = l; l <= r ? i <= r : i >= r;l <= r ? ++i : --i)
#define irep(i,l,r) for(int i = l; i <= r; ++i)
#define drep(i,r,l) for(int i = r; i >= l; --i)
#define yn(x) puts(x?"NO":"YES")

using namespace std;
const int N = 500999;
const int mod = 1000000007;
const int itinf = 1000000000;
const long long llinf = 100000000000000000;

inline ll read(){
	ll s=0,w=1;
	char chcc=getchar();
	while(chcc<'0'||chcc>'9'){if(chcc=='-')w=-1;chcc=getchar();}
	while(chcc>='0'&&chcc<='9') s=s*10+chcc-'0',chcc=getchar();
	return s*w;
}

inline char rc(){
	char readch = getchar();
	while(!('0'<= readch && readch <= '9' || 'A' <= readch && readch <= 'Z' || 'a' <= readch && readch <= 'z'))readch = getchar();
	return readch;
}
map<int,int>mp;
int cur = 0, a[N];
vector<int>e[N];
int main(){
	int T = read();
	while(T --){
		int n = read();
		mp.clear();
		cur = 0;
		irep(i,1,n)a[i] = read();
		irep(i,1,n){
			if(mp.find(a[i] - i) == mp.end())
				mp[a[i] - i] = ++ cur;
		}
		irep(i,1,cur)e[i].clear();
		irep(i,1,n){
			e[mp[a[i]-i]].push_back(a[i]);
		}
		ll ans = 0;
		irep(i,1,cur){
			sort(e[i].begin(),e[i].end());
			for(int j = e[i].size() - 1; j > 0; j -= 2){
				int x = e[i][j], y = e[i][j-1];
				if(x + y >= 0)ans += x+y;
			}
		}
		cout<<ans<<endl;
		
	}
	return 0;
}