#+name: pascals_triangle
#+begin_src python :var n=5 :exports none :return pascals_triangle(5) :results vector
def pascals_triangle(n):
    if n == 0:
        return [[1]]
    prev_triangle = pascals_triangle(n-1)
    prev_row = prev_triangle[n-1]
    this_row = map(sum, zip([0] + prev_row, prev_row + [0]))
    return prev_triangle + [this_row]

#+end_src

#+name: padded_pascals_triangle
#+begin_src emacs-lisp :var data=pascals_triangle
  (let ((max-length (apply #'max (mapcar #'length data))))
    (mapcar (lambda (row)
              (append row (make-vector (- max-length (length row)) "") nil))
            data))
#+end_src

#+begin_src R :var data=padded_pascals_triangle
data
#+end_src

#+RESULTS:
| 1 | nil | nil | nil | nil | nil |
| 1 |   1 | nil | nil | nil | nil |
| 1 |   2 |   1 | nil | nil | nil |
| 1 |   3 |   3 |   1 | nil | nil |
| 1 |   4 |   6 |   4 | 1   | nil |
| 1 |   5 |  10 |  10 | 5   | 1   |