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

MOD = 10 ** 9 + 7

def f(A):
    n = len(A)
    if n == 1:
        return A
    B = [0] * (n - 1)
    for i in range(n - 1):
        B[i] = A[i] + A[i + 1]
        B[i] %= MOD
    return B

for i in range(n - 1):
    A = f(A)

print(A[0])