class PascalsTriangle:
    def __init__(self, N):
        self.N = N
        self._build()

    def __call__(self, n, r):
        if n > self.N:
            raise "INVALID INPUT: input n must be smaller than N"
        if r < 0 or r > N:
            return 0
        return self.nCr[n][r]

    def _build(self):
        tmp = [(1,)]
        for i in range(1, self.N + 1):
            nCi = tuple(1 if j in (0, i)
                        else tmp[-1][j-1] + tmp[-1][j] for j in range(i+1))
            tmp.append(nCi)
        self.nCr = tuple(tmp)


if __name__ == "__main__":
    N = int(input())
    A = list(map(int, input().split()))
    pt = PascalsTriangle(N)

    mod = 10 ** 9 + 7

    ans = 0
    for a, x in zip(A, pt.nCr[N - 1]):
        ans += a * x
        ans %= mod
    print(ans)