#include <bits/stdc++.h>
using namespace std;
#define IO ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
const long long N = 2e5 + 5, MOD = 1e9 + 7, OO = 1e18;
const double PI = acos(-1);
const int dx[4] = {0, 0, 1, -1};
const int dy[4] = {1, -1, 0, 0};

double t, n, a[N];

int main() {
    IO
    cin >> t;
    while (t--) {
        map<double, long long>mp;
        map<double, bool>isUsed;
        long long sm = 0;
        cin >> n;
        for (int i = 1; i <= n; i++) {
            cin >> a[i];
            mp[a[i]]++;
            sm += a[i];
        }
        double k = (double)sm / n;
        long long ans = 0;
        for (int i = 1; i <= n; i++) {
            if (isUsed[a[i]])continue;
            double x = (double)sm - a[i] - k * (n - 2);
            if (mp[x])
                if (x == a[i])ans += mp[a[i]] * (mp[a[i]] - 1) / 2;
                else ans += mp[a[i]] * mp[x];
            isUsed[x] = isUsed[a[i]] = 1;
        }
        cout << ans << '\n';
    }
    return 0;
}