September 2017 Update

Task/Primality-by-trial-division/Clojure/primality-by-trial-division-1.clj

@@ -0,0 +1 @@
+(defn divides? [k n] (zero? (mod k n)))

Task/Primality-by-trial-division/Clojure/primality-by-trial-division-2.clj

@@ -0,0 +1,7 @@
+(defn prime? [x]
+  (or (= 2 x)
+      (= 3 x)
+      (and (< 1 x)
+           (odd? x)
+           (not-any? (partial divides? x)
+                     (range 3 (math/sqrt x) 2)))))

Task/Primality-by-trial-division/Clojure/primality-by-trial-division-3.clj

@@ -0,0 +1,10 @@
+(declare prime?)
+
+(def primes (filter prime? (range)))
+
+(defn prime? [x]
+  (or (= 2 x)
+      (and (integer? x)
+           (< 1 x)
+           (not-any? (partial divides? x)
+                     (take-while (partial > (math/sqrt x)) primes)))))

Task/Primality-by-trial-division/Clojure/primality-by-trial-division.clj

@@ -1,6 +0,0 @@
-(defn divides? [k n] (= (rem n k) 0))
-
-(defn prime? [n]
-  (if (< n 2)
-    false
-    (empty? (filter #(divides? % n) (take-while #(<= (* % %) n) (range 2 n))))))