sol-1.22.tex

To check primality of consecutive odd integers in a specified range we can use this procedure:
\begtt\scm
(define (search-for-primes a b)
  (define (iter i)
    (cond ((< i b) (timed-prime-test i) (iter (+ 2 i)))))
  (iter (if (even? a) (+ 1 a) a)))
\endtt
The results one can obtain by running this procedure over the specified input ranges\fnote{I actually had to use larger input values to measure meaningful results, since the time required to run the tests on the provided input ranges was almost negligible on my machine.} seem to confirm the $\Theta(\sqrt n)$ prediction.