#include "bits/stdc++.h"
using namespace std;
#define ll long long
const int Len = 1e5 + 5;
int n,m;
struct node
{
	int a,b;
	node(){a = b = 0;}
	node(int A,int B){a = A , b = B;}
}sec[Len];
bool cmp(node x,node y){return x.b < y.b;}
bool cmd(node x,node y){return x.a > y.a;}
signed main()
{
	int T;scanf("%d",&T);
	while(T --)
	{
		scanf("%d",&n);
		for(int i = 1 ; i <= n ; i ++)
		{
			scanf("%d",&sec[i].a);
			sec[i].b = sec[i].a - i;
		}
		sort(sec + 1 , sec + 1 + n , cmp);
		//for(int i = 1 ; i <= n ; i ++) printf("woee%d %d\n",sec[i].a,sec[i].b);
		int l = 1 , r = 0;
		ll ans = 0;
		while(l <= n)
		{
			r = l;
			while(r + 1 <= n && sec[r + 1].b == sec[l].b) r ++;
			sort(sec + l , sec + r + 1 , cmd);
			for(int j = l ; j < r ; j += 2)
			{
				if(sec[j].a + sec[j + 1].a >= 0) ans += sec[j].a + sec[j + 1].a;
			} 
			l = r + 1;
		}
		printf("%lld\n",ans);
	}
	return 0;
}