import collections,sys,math,functools,operator,itertools,bisect,heapq,decimal,string,time,random
#sys.setrecursionlimit(10**9)
#sys.set_int_max_str_digits(0)
n = int(input())
#
#alist = []
#s = input()

#for i in range(n):
#    alist.append(list(map(int,input().split())))

alist = list(map(int,input().split()))
mod = 998244353
ans = 0
for i in range(1,n+1):
    if i == 1:
        ans += alist[i-1] * pow(2,n-i-1,mod)
        ans %= mod
        continue
    if i == n:
        ans += alist[i-1] * pow(2,i-2,mod) * (i+1)
        ans %= mod
        continue
    ans += alist[i-1] * pow(2,i-2,mod) * (i+1) * pow(2,n-i-1,mod)
    ans %= mod
print(ans)