Primality by trial division: Difference between revisions

Content added Content deleted

Inline

@@ Line 1,342: / Line 1,342: @@
   (and (> number 1)
        (*prime? 2)))</lang>
+<lang scheme>; twice faster, testing only odd divisors
+(define (prime? n)
+(if (< n 5) (or (= n 2) (= n 3))
+(and (odd? n)
+(let loop ((k 3))
+(or (> (* k k) n)
+(and (positive? (remainder n k))
+(loop (+ k 2))))))))</lang>
 =={{header|Seed7}}==