def nCr(n, r, MOD):
    if n < r:
        return 0
    if n-r < r:
        r = n-r
    comb = 1
    for x in range(n-r+1, n+1):
        comb = (comb * x) % MOD
    d = 1
    for x in range(1, r+1):
        d = (d * x) % MOD
    comb *= pow(d, MOD-2, MOD)
    return comb % MOD
mod=10**9+7

n=int(input())
a=list(map(int,input().split()))
ans=0
for i in range(n):
    ans+=a[i]*nCr(n-1,i,mod)
    ans%=mod
print(ans)