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

ans = A[0] + A[-1]
C = 1
x = 1
y = N-1

for i in range(1,N-1) :
    C = (C*y//x) % (10**9+7)
    ans += (A[i]*C) % (10**9+7)
    y -= 1
    x += 1
print(ans)