MOD = 10**9 + 7

n = int(input())
x = list(map(int, input().split()))
T = sum(x)
sum_x2 = sum(a * a for a in x)
inv_T = pow(T, MOD - 2, MOD)

term = (sum_x2 * inv_T) % MOD
E = ((T + 1) % MOD - term) % MOD
print(E)