@(do (defun hailstone (n)
       (cons n
             (gen (not (eq n 1))
                  (set n (if (evenp n)
                           (trunc n 2)
                           (+ (* 3 n) 1)))))))
@(next :list @(mapcar* (fun tostring) (hailstone 27)))
27
82
41
124
@(skip)
8
4
2
1
@(eof)
@(do (let ((max 0) maxi)
       (each* ((i (range 1 99999))
               (h (mapcar* (fun hailstone) i))
               (len (mapcar* (fun length) h)))
         (if (> len max)
           (progn
             (set max len)
             (set maxi i))))
       (format t "longest sequence is ~a for n = ~a\n" max maxi)))