input: Write a Python function to determine the number of ways to cover a given 3 x n board using 2 x 1 dominoes.
  assert count_ways(2) == 3
  assert count_ways(8) == 153
  assert count_ways(12) == 2131
output: def count_ways(n):
      if n % 2 != 0:
          return 0
  
      DP = [0] * (n + 1)
      DP[0] = 1
      DP[2] = 3
  
      for i in range(4, n + 1, 2):
          DP[i] = 4 * DP[i - 2] - DP[i - 4]
  
      return DP[n]