#include<bits/stdc++.h>
#define ll long long
#define R return
#define pb push_back
#define SI size()

using namespace std;

long long t,n,a[100030],ans,w[5030];

int main(){
    cin >> t;
    while(t--){
        ans = 0;
        memset(w,0,sizeof w);
        cin >> n;
        for(int i=0;i<n;i++)
            cin >> a[i];
        for(int i=0;i<n;i++){
            if(a[i] - w[i] > 1)
                ans += a[i] - w[i] - 1;
            if(a[i] - w[i] < 1)
                w[i+1] += 1 - a[i] + w[i];
            if(a[i] > 1)
                for(int j=i+2;j<=min(i+a[i],n);j++) w[j]++;
        }
        cout << ans << endl;
    }
    return 0;
}

