input: from typing import List
  
  def create_binary_without_adjacent_zeroes(n: int) -> List[str]:
      """
      Given a positive integer n.
  
      A binary sequence is considered valid if every substring of length 2 contains at least one "1".
  
      Provide all valid sequences of length n, in any order.
  
      Examples:
      >>> n = 3
      ['010', '011', '101', '110', '111']
      >>> n = 1
      ['0', '1']
  
      Constraints:
      1 <= n <= 18
      """
output:     def backtrack(current, n):
          if len(current) == n:
              result.append(current)
              return
          if len(current) == 0 or current[-1] == '1':
              backtrack(current + '0', n)
              backtrack(current + '1', n)
          else:  # current[-1] == '0'
              backtrack(current + '1', n)
      
      result = []
      backtrack("", n)
      return result