Dubsoholics Anonymous

Do you feel compulsion to post dubs?
Does it interfere with your daily life?
Do you ever wished to end the dubs cycle?
You've came to the right place.

>>40
(define (check'em n b) (= (mod n b) (mod (div n b) b)))
(define (dubsize dub)
(length (filter (lambda (b) (check'em dub b)) (iota dub 1))))
(define (biggest-dubs upto)
(define (dub-crawler n max bigdubs)
(cond ((= n upto) bigdubs)
((> (dubsize n) max) (dub-crawler (+ n 1) (dubsize n) (list n)))
((= (dubsize n) max) (dub-crawler (+ n 1) max (cons n bigdubs)))
(else (dub-crawler (+ n 1) max bigdubs))))
(dub-crawler 1 1 (list)))
(biggest-dubs 1000)
=> (900)
(dubsize 900)
=> 22