p = 998244353
N = int(input())
A = list(map(int,input().split()))
A.insert(0,0)
a = 1
i = 0
while i<N-2:
    a = (a*2)%p
    i += 1
b = 0
for i in range(1,N+1):
    b = (b+(i+1)*A[i])%p
ans = (a*b)%p
print(ans)