import sys
input = sys.stdin.readline

mod=998244353

N=int(input())
A=list(map(int,input().split()))

ANS=0

def calc(r,l):

    return (l+2)*(r+2)*pow(2,l+r-2,mod)%mod

for i in range(N):
    r=N-1-i
    l=i

    ANS+=A[i]*calc(r,l)
    ANS%=mod
    #print(ANS)

print(ANS%mod)