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

MOD = 998244353
pow2 = [1]*N
for i in range(1, N):
  pow2[i] = pow2[i-1] * 2 % MOD

ans = 0
for i, a in enumerate(A, 1):
  l = (pow2[i-1] + (i-1)*pow2[i-2]) % MOD
  r = ((N-i)*pow2[N-i-1] + pow2[N-i]) % MOD
  ans += a * l * r % MOD

print(ans % MOD)