#include <bits/stdc++.h>
using namespace std;
using ll = long long;

void solve() {
  int n; cin >> n;
  map<ll, vector<ll>> mp;
  for(int i = 0; i < n; i++) {
    ll a; cin >> a;
    mp[a-i].push_back(a);
  }
  ll ans = 0;
  for(const auto& [k, v] : mp) {
    int sz = ssize(v);
    for(int i = sz-1; i-1 >= 0; i -= 2) {
      ans += max(0LL, v[i] + v[i-1]);
    }
  }
  cout << ans << '\n';
}

int main() {
  int t; cin >> t;
  while(t--) solve();
}