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

mod = 10**9+7
factorial = [1]
for n in range(1, N):
    factorial.append( factorial[n-1] * n % mod)

invFact = [0] * (N)
invFact[N-1] = pow(factorial[N-1], mod-2, mod)
for n in range(N-2, -1, -1):
    invFact[n] = invFact[n+1] * (n+1) % mod

def combi(n,m):
    return factorial[n] * invFact[m] * invFact[n-m] % mod
    
coeff = [0] * (N)
for i in range(N):
    coeff[i] = combi( max(N-i, i), min(N-i,i))

ans = 0

for i in range(N):
    ans = (ans + coeff[i] * A[i] % mod) % mod
print(ans)