#include<bits/stdc++.h>
using namespace std;
#define int long long
#define INF 0x3f3f3f3f3f3f3f3f
#define pii pair<int,int>
#define x first
#define y second
#define all(_a) _a.begin()+1, _a.end()
const int N=1010;

bool cmp(pii a,pii b){
    if(a.x!=b.x) return a.x<b.x;
    return a.y>b.y;
}

void solve(){
   int n;
   cin>>n;
   vector<pii> a(n+1);
   for(int i=1;i<=n;i++){
       cin>>a[i].y;
       a[i].x=a[i].y-i;
   }
   sort(all(a),cmp);

   //for(int i=1;i<=n;i++) cout<<a[i].x<<' '<<a[i].y<<endl;
   //cout<<"===="<<endl;

   int sum=0;
   for(int i=2;i<=n;i++){
      if(a[i-1].x==a[i].x&&a[i-1].y+a[i].y>0){
          int s=a[i-1].y+a[i].y;
          sum+=s;
          //cout<<s<<endl;
          i++;
      }
   }
   cout<<sum<<endl;
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    cout << setiosflags(ios::fixed) << setprecision(15);
    int T;
    T=1;
    cin>>T;
    while(T--)solve();
    return 0;
}