using System;
using System.Linq;

class V
{
	static long[] ReadL() => Array.ConvertAll(Console.ReadLine().Split(), long.Parse);
	static void Main()
	{
		var n = int.Parse(Console.ReadLine());
		var a = ReadL();

		if (n == 1)
		{
			Console.WriteLine(a[0] % M);
		}
		else
		{
			var s = a.Select((x, i) => (i + 2) * x % M).Sum() % M;
			Console.WriteLine(s * MPow(2, n - 2) % M);
		}
	}

	const long M = 998244353;
	static long MPow(long b, long i)
	{
		long r = 1;
		for (; i != 0; b = b * b % M, i >>= 1) if ((i & 1) != 0) r = r * b % M;
		return r;
	}
}