n = int(input())
x = list(map(int, input().split()))
n -= 1

mod = 10**9+7
 
#a[i] ~ i**(-1) ~ i**(mod-2) 
a = [0]*(n+1)
for i in range(1, n+1):
    a[i] = pow(i, mod-2, mod)
 
#comb[i] = nCi
comb = [0]*(n+1)
comb[0] = 1

for i in range(1, n+1):
    comb[i] = comb[i-1]*(n-i+1)*a[i]%mod

ans = 0
for i in range(n+1):
    ans += comb[i]*x[i]%mod
print(ans%mod)