#include<bits/stdc++.h>
using namespace std;
#include<atcoder/all>
using namespace atcoder;
using ll = long long;
using mint = modint1000000007;
int n;
vector<int> x;

void solve(){
	ll s = 0;
	for(auto &i:x)s+=i;
	mint ans = 0;
	for(int i = 0;i<n;i++){
		ans += mint(s-x[i])*mint(x[i])/s;
	}
	ans++;
	cout<<ans.val()<<endl;
}

signed main(){
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	cin >> n;
	x = vector<int>(n);
	for(auto &i:x)cin >> i;
	solve();
}