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Problem 9¶

#!r6rs
#!chezscheme

(import (chezscheme))

(define answer-9
  (let loop1 ((a 1))
    (if (< 333 a)
      (error "answer-9" "answer-9 was not found!")
      (let loop2 ((b a))
        (if (< 499 b)
          (loop1 (add1 a))
          (let ((c (- 1000 a b)))
            (if (= (+ (expt a 2) (expt b 2)) (expt c 2))
              (* a b c)
              (loop2 (add1 b)))))))))

(printf "9: ~D~%" answer-9)