MOD = 998_244_353
N = int(input())
A = list(map(int, input().split()))

C = [0]*N
for i in range(N):
   C[i] = pow(2, i, MOD) + i * pow(2, i-1, MOD)
   C[i] %= MOD
   C[i] *= pow(2, N-i-1, MOD) + (N-i-1) * pow(2, N-i-2, MOD)
   C[i] %= MOD

ans = 0
for a, c in zip(A, C):
   ans += a*c
   ans %= MOD
print(ans)