N = int(input())
A = list(map(int, input().split()))
mod = 998244353
ans = 0
two = [1] * (N + 1)
for i in range(N):
    two[i + 1] = two[i] * 2
    two[i + 1] %= mod

for i in range(N):
    ans += (two[i] + i * two[i - 1]) * A[i] * two[N - 1 - i]
    ans %= mod
print(ans)