title: I need a function to list all multiples of 3 in the previous output in decending order
body: <p>I'm trying to participate in a coding challenge, and I have part of the code complete, but now I need a function to list all multiples of 3 in the previous output in descending order.</p>
  
  <p>Is there a function you could do that would run all the previous numbers printed in the triangle and divide it by 3,and then print the numbers that came out as a whole number from that calculation? Or some other similar task to come up with all the multiples of 3 up to line 50 in Pascal's Triangle?</p>
  
  <pre><code>def generate_pascals_triangle(rows):
      triangle = [[1], [1, 1]]
      if rows == 1:
          return triangle[0]
      else:
          for row_number in range(2, rows):
              triangle.append([1]*row_number)
              for number in range(1, row_number):
                  triangle[row_number][number] = (triangle[row_number-1][number-1]+triangle[row_number-1][number])
              triangle[row_number].append(1)
          return triangle
  def difference_between_rows(row, next_row):
      row_len = 0
      next_row_len = 0
      for number in row:
          string_number = str(number)
          row_len += (len(string_number)+1)
      for number in next_row:
          string_number = str(number)
          next_row_len += (len(string_number)+1)
      return (next_row_len-1) - (row_len-1)
  def print_pascals_triangle(triangle):
      largest_element = triangle[-1][len(triangle[-1]) // 2]
      element_width = len(str(largest_element))
      def format_row(row):
          return ' '.join([str(element).center(element_width) for element in row])
      triangle_width = len(format_row(triangle[-1]))
      for row in triangle:
          print(format_row(row).center(triangle_width))
  if __name__ == '__main__':
          rows = 51
          print_pascals_triangle(generate_pascals_triangle(rows))
  </code></pre>