1.lisp

;; If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.
;; Find the sum of all the multiples of 3 or 5 below 1000.


(let ((sum 0))
  (loop for a from 1 to 999
		if (or (= (mod a 3) 0) (= (mod a 5) 0))
		  do (incf sum a)
		)
  (print sum)
  )


;; Output 233168