N = int(input())
A = list(map(int, input().split()))

mod = 10 ** 9 + 7
div3 = pow(3, mod-2, mod)

ans = 0
head = 1
tail = 2 * pow(3, N - 1, mod) % mod
for i, a in enumerate(A):
    head = head * a % mod
    tail = tail * div3 % mod
    if i == N - 1:
        tail = 1
    ans += head * tail % mod
    ans %= mod

print(ans)