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

C = [1]

x = 1
y = N-1
for i in range(1,N-1) :
    C.append(C[-1] * y // x)
    x += 1
    y -= 1
C.append(1)

ans = 0
for i in range(N) :
    ans += A[i] * C[i]
ans %= 10**9+7
print(ans)