import sys
input=sys.stdin.readline

N=int(input())
A=[0]+list(map(int,input().split()))
Mod=998244353

if N==1:
    print(A[1]%Mod)
    exit(0)

X=0
for i in range(1,N+1):
    X+=(i+1)*A[i]
    X%=Mod

print((X*pow(2,N-2,Mod))%Mod)