N = int(input())
a = list(map(int,input().split()))
ans = 0
P = 998244353
for i in range(N):
    i += 1
    tmp = pow(2,N-i,P) * (pow(2,i-1,P)+(i-1)*pow(2,i-2,P))%P
    ans += a[i-1] * tmp
    ans %= P
print(ans)