SICP in Clojure: Chapter 1, Exercise 12

This is my Clojure solution to Chapter 1, Exercise 12:

(ns sicp.ch1.ex12)

(defn pascal
  [i j]
  (if (or (zero? j) (= i j))
    1
    (+ (pascal (dec i) (dec j)) (pascal (dec i) j))))

(for [i (range 10)]
  (for [j (range (inc i))]
    (pascal i j))) ; Pascal's triangle