#include<iostream>
#include<cstdio>
using namespace std;
long long n, num[5005], t, ans;

int main() {
	cin >> n;
	for (long long i = 1; i <= n; i++) {
		cin >> t;
		num[t]++;
	}
	for (long long i = 1; i <= 5000; i++) {
		for (long long j = i; j <= 5000; j++) {
			if (num[i] && num[j] && num[i + j] >= 2) {
				if (i == j) {
					ans += num[i] % 1000000007 * (num[i] - 1) / 2 % 1000000007 * num[i + j] % 1000000007 * (num[i + j] - 1) % 1000000007 / 2;
					ans %= 1000000007;
				}
				else {
					ans += num[i] % 1000000007 * num[j] % 1000000007 * num[i + j] % 1000000007 * (num[i + j] - 1) % 1000000007 / 2;
					ans %= 1000000007;
				}
			}
		}
	}
	cout << ans << endl;
	return 0;
}