## https://yukicoder.me/problems/no/2717

MOD = 998244353

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

    answer = 0
    for i in range(N):

        ans = pow(2, N - 1, MOD)
        if N >= 2:
            ans += ((N - 1) * pow(2, N - 2, MOD)) % MOD
            ans %= MOD
        if N >= 3:
            b = (i * (N - 1 - i)) % MOD
            b *= pow(2, N - 3, MOD)
            b %= MOD
            ans += b
            ans %= MOD

        ans *= A[i]
        ans %= MOD
        answer += ans
        answer %= MOD
    print(answer)


 



if __name__ == "__main__":
    main()