N = int(input())
A = list(map(int, input().split()))

mod = 10 ** 9 + 7
n = 2 * N
fact = [1] * (n + 1)
invfact = [1] * (n + 1)
for i in range(1, n):
    fact[i + 1] = ((i+1) * fact[i]) % mod
invfact[n] = pow(fact[n], mod - 2, mod)
for i in range(n - 1, -1, -1):
    invfact[i] = invfact[i + 1] * (i + 1) % mod

def comb(n, r):
    if n < 0 or r < 0 or n - r < 0:
        return 0
    return fact[n] * invfact[r] * invfact[n - r] % mod


ans = 0
for i in range(N):
    ans += comb(N - 1, i) * A[i]
    ans %= mod
    
print(ans)