n = int(input())
A = list(map(int, input().split()))
mod = 10**9 + 7
for i in range(n - 1):
    NA = [0 for _ in range(n)]
    for j in range(n - i - 1):
        NA[j] = (A[j] + A[j + 1]) % mod
    A = NA[:]
print(A[0])