def main():
    import sys
    input=sys.stdin.readline
    mod=998244353
    n=int(input())
    a=list(map(int,input().split()))
    
    pow2=[1]*n
    for i in range(1,n):
        pow2[i]=pow2[i-1]*2%mod
    
    ans=0
    for i in range(n):
        ans=(ans+a[i]*((pow2[i]+pow2[i-1]*i)*pow2[n-i-1]))%mod
    print(ans)
main()