input: def sierpinski_triangle(n):
      """
      Generate the first n rows of the Sierpinski triangle.
      The Sierpinski triangle is a fractal and attractive fixed set with the overall shape of an equilateral triangle, subdivided recursively into smaller equilateral triangles.
      This function prints the binary representation of the triangle up to row n.
  
      >>> sierpinski_triangle(3)
           1 
         1 0 1 
       1 0 1 0 1 
      >>> sierpinski_triangle(4)
               1 
             1 0 1 
           1 0 1 0 1 
         1 0 1 0 1 0 1 
      """
      for i in range(n):
          for k in range(n - i + 1):
              print(end=" ")
          for j in range(i + 1):
              print('1' if j & i else '0', end=" ")
          print()
output:     for i in range(n):
          for k in range(n - i + 1):
              print(end=" ")
          for j in range(i + 1):
              print('1' if j & i else '0', end=" ")
          print()