Project Euler 1 in Scheme

@timgallant

;; e1
 
(define (mod-three-or-five? x)
  (if (or
       (= (modulo x 3) 0)
       (= (modulo x 5) 0)) #t #f))
 
(define (e1 x)
  (sum
   (filter
    mod-three-or-five?
    (iota x))))