/**
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⡀⠀⠀⠀⠀⢀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⡖⠁⠀⠀⠀⠀⠀⠀⠈⢲⣄⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⣼⡏⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⣧⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⣸⣿⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⣿⣇⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⣿⣿⡇⠀⢀⣀⣤⣤⣤⣤⣀⡀⠀⢸⣿⣿⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⢻⣿⣿⣔⢿⡿⠟⠛⠛⠻⢿⡿⣢⣿⣿⡟⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⣀⣤⣶⣾⣿⣿⣿⣷⣤⣀⡀⢀⣀⣤⣾⣿⣿⣿⣷⣶⣤⡀⠀⠀⠀⠀
⠀⠀⢠⣾⣿⡿⠿⠿⠿⣿⣿⣿⣿⡿⠏⠻⢿⣿⣿⣿⣿⠿⠿⠿⢿⣿⣷⡀⠀⠀
⠀⢠⡿⠋⠁⠀⠀⢸⣿⡇⠉⠻⣿⠇⠀⠀⠸⣿⡿⠋⢰⣿⡇⠀⠀⠈⠙⢿⡄⠀
⠀⡿⠁⠀⠀⠀⠀⠘⣿⣷⡀⠀⠰⣿⣶⣶⣿⡎⠀⢀⣾⣿⠇⠀⠀⠀⠀⠈⢿⠀
⠀⡇⠀⠀⠀⠀⠀⠀⠹⣿⣷⣄⠀⣿⣿⣿⣿⠀⣠⣾⣿⠏⠀⠀⠀⠀⠀⠀⢸⠀
⠀⠁⠀⠀⠀⠀⠀⠀⠀⠈⠻⢿⢇⣿⣿⣿⣿⡸⣿⠟⠁⠀⠀⠀⠀⠀⠀⠀⠈⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣼⣿⣿⣿⣿⣧⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠐⢤⣀⣀⢀⣀⣠⣴⣿⣿⠿⠋⠙⠿⣿⣿⣦⣄⣀⠀⠀⣀⡠⠂⠀⠀⠀
⠀⠀⠀⠀⠀⠈⠉⠛⠛⠛⠛⠉⠀⠀⠀⠀⠀⠈⠉⠛⠛⠛⠛⠋⠁⠀⠀
**/
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define nl cout<<"\n";
#define ll long long int
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define F(i,a,b) for(i=a;i<b;i++)
//#include <ext/pb_ds/assoc_container.hpp> // policy based data structure header files
//#include <ext/pb_ds/tree_policy.hpp> // policy based data structure header files
#define IOS ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
//using namespace __gnu_pbds; // for pbds
//#define ordered_set tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> // have functions like order_of_key, find_by_order
const double PI = 3.14159265358979323846264338327950288419716939937510582097494459230781641;
const ll M=1e16;
const ll MAXN=100200;
ll i,j,mask;
void solve()
{
    ll n;
    cin>>n;
    vector<ll> v(n+4),cnt(n+4);
    F(i,1,n+1)
    {
        cin>>v[i];
    }
    ll ans=0;
    F(i,1,n+1)
    {
        cnt[i]+=cnt[i-1];
        if(v[i]-cnt[i]>1)
        {
            ans+=v[i]-cnt[i]-1;
        }
        if(i<n-1 && v[i]!=1)
        {
            ll l=min(n,i+v[i]);
            cnt[i+2]+=1;
            cnt[l+1]-=1;
        }
        if(cnt[i]-(v[i]-1)>=0)
        {
            cnt[i+1]+=cnt[i]-(v[i]-1);
            cnt[i+2]-=(cnt[i]-(v[i]-1));
        }
    }
    cout<<ans;
}
int main()
{
IOS
/*#ifndef ONLINE_JUDGE
   freopen("input.txt","r",stdin);
   freopen("output.txt","w",stdout);
#*/
ll t,test=1;
cin>>test;
F(t,1,test+1)
{
    //cout<<"Case #"<<t<<": ";
    solve();
    nl
}
return 0;
}
