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

res = 0
mod = 998244353

for i in range(1,N+1):
    res += (a[i-1]*((i-1)*pow(2,max(0,i-2),mod)+pow(2,i-1,mod))*pow(2,N-i,mod))%mod
    res %= mod
print(res)