from functools import reduce
mod = 10 ** 9 + 7
def cmb(n,r,mod):
    numerator = reduce(lambda x, y: x * y % mod, [n - r + k + 1 for k in range(r)])
    denominator = reduce(lambda x, y: x * y % mod, [k + 1 for k in range(r)])
    return numerator * pow(denominator, mod - 2, mod) % mod
N=int(input())
nCr=[]
for i in range(N-2):
    nCr.append(cmb(N-1,i+1,mod))
A=list(map(int,input().split()))
ans=A[0]+A[N-1]
for i in range(N-2):
    ans+=nCr[i]*A[i+1]
    ans%=mod
print(ans)