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

mod = 10**9+7

import copy
for i in range(1, n):
    A_ = copy.copy(A)
    for j in range(n-i):
        A_[j] = A[j]+A[j+1]
        A_[j] %= mod
    A = copy.copy(A_)
print(A[0]%mod)