def c(a,b):
    c,d=1,1
    for i in range(b):
        c*=a-i
        d*=i+1
    return c/d

n=int(input())
a=map(int,input.split())
r=0
for i in range(n):
    r=(r+a[i]*c(n-1,i))%(10**9+7)
print(r)