using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    static string[] SList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => ReadLine()).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var a = NList;
        var ans = 0L;
        var n2 = new long[n + 1];
        n2[0] = 1;
        for (var i = 1; i < n2.Length; ++i) n2[i] = n2[i - 1] * 2 % mod;
        for (var i = 0; i < n; ++i)
        {
            ans = (ans + a[i] * Calc(i, n2) % mod * Calc(n - i - 1, n2) % mod) % mod;
        }
        WriteLine(ans);
    }
    static int mod = 998_244_353;
    static long Calc(int i, long[] n2)
    {
        if (i < 1) return 1;
        return n2[i - 1] * (i + 2) % mod;
    }
}