A little program that uses recursion, and uses combinations to draw out Pascal's Triangle.

pascal.scala

object Main extends App {
  
  // Find any place in the triangle using n choose k
  def pascal2(r: Int, c: Int): Int = {
    def factorial(n: Int): Int =
      if (n < 1) 1 else n * factorial(n - 1)
    factorial(r) / (factorial(c) * factorial(r - c))
  }

  def pascal(r: Int, c: Int): Int = {
    if (c == 0 || c == r) 1
    else pascal(r - 1, c - 1) + pascal(r - 1, c)
  }
  
  def triangle(totalRows: Int, op: (Int, Int) => Int) = {
    var list: String = ""
    (0 to totalRows).foreach(row => {
      (0 until totalRows - row).foreach(space => list += "  ")
      (0 to row).foreach(col => {
        list += op(row, col).toString.padTo(4, ' ')
      })
      list += "\n"
    })
    
    list
  }
  
  print(triangle(6, pascal))
  print(triangle(6, pascal2))
}

/*
            1   
          1   1   
        1   2   1   
      1   3   3   1   
    1   4   6   4   1   
  1   5   10  10  5   1   
1   6   15  20  15  6   1   
            1   
          1   1   
        1   2   1   
      1   3   3   1   
    1   4   6   4   1   
  1   5   10  10  5   1   
1   6   15  20  15  6   1   
*/