import sys; input = sys.stdin.buffer.readline sys.setrecursionlimit(10**7) from collections import defaultdict con = 10 ** 9 + 7; INF = float("inf") def getlist(): return list(map(int, input().split())) class Combination(object): def __init__(self, N, con): self.fac = [0] * (N + 1) self.inv = [0] * (N + 1) self.finv = [0] * (N + 1) self.fac[0], self.fac[1] = 1, 1 self.inv[1] = 1 self.finv[0], self.finv[1] = 1, 1 # 前計算 for i in range(2, N + 1): self.fac[i] = self.fac[i - 1] * i % con self.inv[i] = self.inv[con % i] * (con - (con // i)) % con self.finv[i] = self.finv[i - 1] * self.inv[i] % con def com(self, N, k): return (self.fac[N] * self.finv[k] * self.finv[N - k]) % con #処理内容 def main(): N = int(input()) A = getlist() ans = 0 Com = Combination(N - 1, con) for i in range(N): ans += A[i] * Com.com(N - 1, i) ans %= con print(ans) if __name__ == '__main__': main()