Comment by kunqiana

I tried to recode what you did in scheme for practice

    (define (pascal n)
      (if (= n 0) (list 1)
       (begin
       (let ((L (pascal (- n 1)))
           (ret (list 1))) 
       (do ((i 0 (+ i 1)))
           ((= i (- (length L) 1)))
           (begin (set! ret (append ret (list (+ (list-ref L    i) (list-ref L (+ i 1))))))))
       (append ret (list 1))
        ))))