nCr = {}
def cmb(n, r):
    if r == 0 or r == n: return 1
    if r == 1: return n
    if (n,r) in nCr: return nCr[(n,r)]
    nCr[(n,r)] = cmb(n-1,r) + cmb(n-1,r-1)
    return nCr[(n,r)]
N=int(input())
a=[*map(int,input().split())]
ans=a[0]+a[N-1]
for i in range(1,N-1):
    ans+=a[i]*(cmb(N-1,i))
print(int(ans%1000000007))