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#lang racket
(require "common.rkt")
; Find the product of the coefficients, a and b, for the quadratic expression
; that produces the maximum number of primes for consecutive values of n,
; starting with n = 0.
(define (solve)
(define (make-pairs n)
(define v (range (- n) n))
(cartesian-product v v))
(define (consecutive a b)
(define (helper n)
(if (not (is-prime? (+ (* n n) (* a n) b))) n (helper (add1 n))))
(helper 0))
(apply * (second
(foldr (lambda (x y) (if (> (first x) (first y)) x y))
'(0)
(map (lambda (x) (list (consecutive (first x) (second x)) x))
(make-pairs 1000))))))
(provide solve)
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