Contents

;;; perfect-numbers.el --- perfect-numbers Exercise (exercism)

;;; Commentary:

;;; Code:

(require 'cl)


(defun divisors (n)
  (cl-loop for i from 1 to (truncate (sqrt n))
           if (= (% n i) 0) collect i
           and if (not (= i (/ n i))) collect (/ n i)))


(defun sum-divisors (n)
  ;; Remove n from the list and add'em up.
  (apply '+ (cdr (sort (divisors n) '>))))


(defun perfect-numbers (n)
  (cl-loop for i from 2 to n by 2
           when (= i (sum-divisors i))
           collect i))


(provide 'perfect-numbers)
;;; perfect-numbers.el ends here

Version data entries

395 entries across 395 versions & 1 rubygems

Version	Path
trackler-2.2.1.139	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.138	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.137	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.136	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.135	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.134	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.133	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.132	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.131	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.130	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.129	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.128	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.127	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.126	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.125	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.124	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.123	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.122	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.121	tracks/elisp/exercises/perfect-numbers/example.el
trackler-2.2.1.120	tracks/elisp/exercises/perfect-numbers/example.el