Рекурсия, IF, новичок

(defun add(e l) (append l (list e))) 
(defun check(x) (cond ((eq x 2) (true)) ((> x 1) (loop for i from 2 to (+ (sqrt x) 1) do (if (eq (mod x i) 0) (return (false))) (return (true)))))) 
(defun nums(n l x) ((if (check x) (add x l)) (if (eq x n) (l) (nums n l (+ x 1)))))

(defun check(x) 
    (cond ((eq x 2) t) 
          ((> x 1) (not (iter (for i from 2 to (flo2fix (+ (sqr x) 1)))
                              (when (and (<> x i) (= (% x i) 0)) (return t)) ))))) 
 
==> check
 
(defun nums(n l x) 
 (cond ((= x n) l)
       ((check x) (nums n (cons x l) (+ x 1)))
       (t (nums n l (+ x 1)))))
 
==> nums
 
(nums 30 nil 1)
 
==> (29 23 19 17 13 11 7 5 3 2)

(defun nums(n l x) 
  ((if (check x) (add x l)) ;; лишняя левая скобка
   (if (eq x n) (l) (nums n l (+ x 1)))))

(defun check (x)
  (cond ((eq x 2) t)
        ((> x 1) (loop for i from 2 to (+ (sqrt x) 1)
                       when (zerop (mod x i)) return nil 
                       finally (return t)))))
 
(defun nums (n x)
  (labels ((helper (n l x)
             (cond ((= x n) l)
                   ((check x) (helper n (cons x l) (1+ x)))
                   (t (helper n l (1+ x))))))
    (nreverse (helper n () x))))

(defun check (x)
  (when (> x 1) (loop for i from 2 to (1+ (sqrt x))
                      never (zerop (mod x i)))))
 
(defun nums(x n &optional w) 
  (cond ((= x n) (nreverse w))
        ((or (= x 2) (check x)) (nums (1+ x) n (cons x w)))
        ((nums (1+ x) n w))))
 
> (nums 1 30)
(2 3 5 7 11 13 17 19 23 29)

(defun nums(x n &optional w) 
  (cond ((= x n) (nreverse w))
        ((or (= x 2) (when (> x 1)
                       (loop for i from 2 to (1+ (sqrt x))
                             never (zerop (mod x i)))))
         (nums (1+ x) n (cons x w)))
        ((nums (1+ x) n w))))
 
> (nums 1 30)
(2 3 5 7 11 13 17 19 23 29)

(defun nums (n x)
  (do ((w nil (if (check x) (cons x w) w))
       (x x (1+ x)))
      ((= x n) (nreverse w))))

(defun nums(x n &optional w) 
  (cond ((= x n) (nreverse w))
        ((check x) (nums (1+ x) n (cons x w)))
        ((nums (1+ x) n w))))

(defun prime-list (n)
  (let ((res nil))
     (iter (for m upfrom 2)
        (when (not
         (iter (for k from 2 to (1+ (flo2fix (sqr m))))
               (when (and (<> m k)(zerop (% m k))) (return t)))) (collecting m into res))
        (when (= (length res) n) (return res)))))
 
==> prime-list
 
(prime-list 10)
 
==> (2 3 5 7 11 13 17 19 23 29)
 
(prime-list 50)
 
==> (2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197 199 211 223 227 229)

(defun check (n)
  (when (> n 1) (loop for a from 2 to (1+ (sqrt n))
                      never (zerop (mod n a)))))
 
(defun nums(n m) 
  (loop for a from n to m
        when (or (= a 2) (check a)) collect a))
 
> (nums 1 30)
(2 3 5 7 11 13 17 19 23 29)