MOD = 10 ** 9 + 7
n = int(input())
a = list(map(int, input().split()))
s = [1]
for x in a:
    s.append(s[-1] * x % MOD)
pow3 = [1]
for _ in range(n):
    pow3.append(pow3[-1] * 3 % MOD)

ans = 0
for i in range(1, n):
    ans += s[i] * 2 * pow3[n - 1 - i]
    ans %= MOD
ans += s[n]
ans %= MOD
print(ans)