N =int(input())
A =[int(i)for i in input().split()]

def cmb(n,r,mod):
    if (r<0 or r>n):
        return 0
    r = min(r,n-r)
    #n!/(r!(n-r)!)
    return g1[n]*g2[r]*g2[n-r] %mod #nCrのmod

mod = 10**9+7
g1 =[1,1] #i番目=i!の元
g2 =[1,1] #i番目=i!の逆元
inverse =[0,1] #i番目=iの逆元

for i in range(2,N+1):
    g1.append(g1[-1]*i %mod) #i!の元の追加
    inverse.append(-inverse[mod % i] * (mod//i) % mod) #???(iの逆元を計算してるはず)
    g2.append((g2[-1]*inverse[-1])%mod)

ans = 0
for i in range((N+1)//2):
    a =A[i] +A[N-1-i]
    ans += a * cmb(N-1,i,mod) % mod
if N%2==1:
    n = N//2
    ans -= A[n] * cmb(N-1,n,mod) % mod

print(ans%mod)