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#lang racket
(require "../../shared/lists.rkt")
(require "../../shared/chapter1.rkt")
(define (enumerate-interval j k)
(define (iter i interval)
(if (< i j)
interval
(iter (- i 1) (cons i interval))))
(iter k '()))
((lambda ()
(newline)
(display (enumerate-interval 2 5))))
(define (unique-pairs n)
(flatmap
(lambda (i)
(map (lambda (j) (list j i))
(enumerate-interval 1 (- i 1))))
(enumerate-interval 1 n)))
(define (prime? n)
(fermat? 2 n))
(define (prime-sum? pair)
(prime? (+ (car pair) (cadr pair))))
(define (make-pair-sum pair)
(list (car pair) (cadr pair)
(+ (car pair) (cadr pair))))
(define (prime-sum-pairs n)
(map make-pair-sum
(filter prime-sum? (unique-pairs n))))
((lambda ()
(display "unique-pairs")
(newline)
(display (unique-pairs 10))
(newline)
(display "prime-sum-pairs")
(newline)
(display (prime-sum-pairs 10))
(newline)))
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