#include <bits/stdc++.h>
#define int long long
using namespace std;

int read(){
    int res=0,sign=1;char ch=getchar();
    for(;ch<'0'||ch>'9';ch=getchar())if(ch=='-')sign=-sign;
    for(;ch>='0'&&ch<='9';ch=getchar()){res=(res<<3)+(res<<1)+(ch^'0');}
    return res*sign;
}

#define rep(i,l,r) for(int i=l;i<=r;++i)
#define dep(i,r,l) for(int i=r;i>=l;--i)

const int N=1e5+10;

typedef long long ll;

int n;
ll a[N];

bool cmp(int x,int y){
    return a[x]>a[y];
}

void solve(){
    n=read();
    rep(i,1,n)a[i]=read();
    map<ll,vector<int>> mp;
    rep(i,1,n)mp[a[i]-i].push_back(i);
    ll ans=0;
    for(auto&& [val,vec]:mp){
        auto cur=vec;
        sort(cur.begin(),cur.end(),cmp);
        // for(auto&& i:cur){
        //     printf("%d ",i);
        // }puts("");
        for(int i=0;i+1<cur.size();i+=2){
            if(a[cur[i]]+a[cur[i+1]]>=0){
                ans+= a[cur[i]]+a[cur[i+1]];       
            }else break;
        }
    }
    printf("%lld\n",ans);
}

signed main(){ 
    int t=read();
    while(t--)solve();
}

/*
3
9
3 -5 5 6 7 -1 9 1 2
3
-5 -4 -3
3
1 10 100
*/