import sys
sys.setrecursionlimit(5*10**5)
input = sys.stdin.readline
from collections import defaultdict, deque, Counter
from heapq import heappop, heappush
from bisect import bisect_left, bisect_right
from math import gcd

n = int(input())
a = list(map(int,input().split()))
mod= 998244353
x = [1,3]
for i in range(2,202020):
    x.append(x[-1]*2+pow(2,i-1, mod))
    x[-1] %= mod
ans = 0
for i in range(n):
    l = i
    r = n-i-1
    tmp = x[l] * x[r]
    tmp %= mod
    ans += tmp*a[i]
    ans %= mod

print(ans)