MOD = 998244353

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

if n == 1:
  ans = sum(a) % MOD
  print(ans)
  exit()

ans = 0
for i in range(n):
	ans = (ans + (i + 2) * a[i]) % MOD

ans = (ans * pow(2, n - 2, MOD)) % MOD
print(ans)