/**
 *    title:  g.cpp
 *    author:  Proaes Meluam
 *    created:  2024-09-27 13:40:01
**/
#include <bits/stdc++.h>
#ifdef LOCAL
#include "algo/debug.h" 
#else
#define debug(...) 42
#endif
using namespace std;
using ll = long long;
using ull = unsigned long long;
const double pi = acos(-1);
const double E = exp(1);
constexpr ll mod = 1e9 + 7;
// constexpr int inf = 0x3f3f3f3f;
constexpr ll inf = 0x3f3f3f3f3f3f3f3f;
int main() {
    cin.tie(nullptr)->sync_with_stdio(false);

    int tt = 1;
    cin >> tt;
    while (tt--) {
        int n;
        cin >> n;
        map<ll, multiset<ll>>mp;
        for (ll i = 1; i <= n; ++ i) {
            ll ai;
            cin >> ai;
            mp[i - ai].insert(-ai);
        }
        ll ans = 0;
        for (auto [p, st] : mp) {
            int cur = 1;
            ll pre = -1;
            for (auto i : st) {
                if (cur & 1) {
                    pre = -i;
                } else { // even
                    if (-i + pre > 0) {
                        ans += -i + pre;
                    } else {
                        break;
                    }
                }
                cur ++;
            }
        }
        cout << ans << "\n";
    }
}