(collect
    (subseries
     (map-fn t
             (lambda (triplet)
               (destructuring-bind (c b a) triplet
                 (list a b c)))
             (choose-if (lambda (triplet)
                          (destructuring-bind (c b a) triplet
                            (= (expt c 2)
                               (+ (expt b 2)
                                  (expt a 2)))))
                        (scan-fn t
                                 (lambda ()
                                   (list 1 1 1))
                                 (lambda (triplet)
                                   (destructuring-bind (c b a)
                                       triplet
                                     (cond ((< a b)
                                            (list c b (1+ a)))
                                           ((< b c)
                                            (list c (1+ b) 1))
                                           (t
                                            (list (1+ c) 1 1))))))))
     0 10))