using System.Collections;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

internal class Program
{
    private const long mod = 998244353;
    private const long mod17 = 1000000007;
    private const long INF = mod17 * mod17;
    
    public static long mod_pow(long x, long n, long m = mod)
    {
        x %= m;
        if (x < 0) x += m;
        long res = 1;
        while (n > 0)
        {
            if ((n & 1) != 0) res = res * x % m;
            x = x * x % m;
            n >>= 1;
        }

        return res;
    }
    public struct perm
    {
        public List<int> fact;
        public List<int> factinv;

        public perm(int n)
        {
            fact = new List<int>(n);
            factinv = new List<int>(n);
            fact.Add(1);
            for (int i = 1; i < n; i++)
            {
                long val = fact.Last();
                val = val * i % mod;
                fact.Add((int)val);
            }

            long las = fact.Last();
            long cur = mod_pow(las, mod - 2);
            factinv.Add((int)cur);
            for (int i = n - 1; i > 0; i--)
            {
                long val = factinv.Last();
                val = val * i % mod;
                factinv.Add((int)val);
            }

            factinv.Reverse();
        }

        public int comb(int a, int b)
        {
            if (a < 0 || b < 0 || a < b) return 0;
            long res = fact[a];
            res = res * factinv[b] % mod;
            res = res * factinv[a - b] % mod;
            return (int)res;
        }
    }
    
    public static void Main(string[] args)
    {
        var n = int.Parse(Console.ReadLine());
        perm pm = new perm(n + 5);
        var a = getar();
        long ans = 0;
        for (int i = 0; i < n; i++)
        {
            long coef = 1;
            if (i < n - 1) coef = mod_pow(2, n - 2 - i);
            coef = coef * a[i] % mod;
            long csum = 0;
            /*for (int j = 1; j <= i + 1; j++)
            {
                long val = pm.comb(i, j - 1);
                val = val * j % mod;
                csum += val;
                if (csum >= mod) csum -= mod;
            }*/
            csum = 1;
            if (i > 0)
            {
                csum = i + 2;
                csum = csum * mod_pow(2, i - 1) % mod;
            }

            ans += csum * coef;
            ans %= mod;
            //Console.WriteLine(csum);
        }
        Console.WriteLine(ans);
    }
    public class lower_bound<T> : IComparer<T> where T : IComparable<T>
    {
        public int Compare(T x, T y)
        {
            return 0 <= x.CompareTo(y) ? 1 : -1;
        }
    }
    public static List<T> mkar<T>(int n, T val)
    {
        List<T> res = new List<T>(n);
        for(int i=0;i<n;i++)res.Add(val);
        return res;
    }

    public static int[] getar()
    {
        var res = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        return res;
    }
}