#include <bits/stdc++.h>
#define MAXN ((int) 1e5)
#define MOD ((int) 1e9 + 7)
using namespace std;

int n, A[MAXN + 10];
long long ans;

long long power(long long a, long long b) {
    long long y = 1;
    for (; b; b >>= 1) {
        if (b & 1) y = y * a % MOD;
        a = a * a % MOD;
    }
    return y;
}

long long inv(long long x) {
    return power(x, MOD - 2);
}

int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) scanf("%d", &A[i]);

    long long sm = 0;
    for (int i = 1; i <= n; i++) sm += A[i];
    sm %= MOD;

    ans = 0;
    for (int i = 1; i <= n; i++) ans = (ans + (sm - A[i] + MOD) * A[i]) % MOD;
    ans = ans * inv(sm) % MOD;
    printf("%lld\n", (ans + 1) % MOD);
    return 0;
}