## https://yukicoder.me/problems/no/1325

MOD = 998244353

def main():
    N = int(input())
    A = list(map(int, input().split()))

    answer = 0
    pow1 = pow(2, N - 1, MOD)
    pow2 = pow(2, N - 2, MOD)
    for i in range(N):
        a2 = (A[i] * pow1) % MOD

        a1 = (A[i] * i) % MOD
        a1 *= pow2
        a1 %= MOD

        a = a1 + a2
        a %= MOD
        answer += a
        answer %=MOD

    print(answer)






        

    



if __name__ == "__main__":
    main()