def main():
    import sys
    input=sys.stdin.readline
    mod=998244353
    n=int(input())
    a=list(map(int,input().split()))
    
    p=pow(2,n-2,mod)
    
    ans=0
    for i in range(n):
        ans=(ans+a[i]*(p*2+i*p))%mod
    print(ans)
main()