(defun r (n c &optional (s ""))
(if (> n 0)
(r (- n 1) c (concatenate 'string c s))
s))
(defun s (n) (concatenate 'string (r (truncate n 2) " ") "+"))
(defun p (n)
(dotimes (x n)
(if (= x (truncate n 2))
\x09(write-line (r n "+"))
(write-line (s n)))))
(p (parse-integer (read-line)))
Note that non-ascii characters in the above source code will be escaped (such as \x9f).