18 lines
609 B
Scheme
18 lines
609 B
Scheme
(define prime?
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(let ((wheel '(1 2 2 . #1=(4 2 4 2 4 6 2 6 . #1#))))
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(lambda (n)
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(if (< n 2)
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#f
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(let loop ((f 2) (w wheel))
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(cond
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((> (* f f) n) #t)
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((zero? (remainder n f)) #f)
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(#t (loop (+ f (car w)) (cdr w)))))))))
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(define (deceptives n)
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(let loop ((k 2) (r 1) (n n) (l '()))
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(if (zero? n)
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(reverse! l)
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(if (and (not (prime? k)) (zero? (remainder r k)))
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(loop (+ k 1) (+ (* 10 r) 1) (- n 1) (cons k l))
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(loop (+ k 1) (+ (* 10 r) 1) n l)))))
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