Initial data commit

Task/Totient-function/Kotlin/totient-function.kotlin

@@ -0,0 +1,37 @@
+// Version 1.3.21
+
+fun totient(n: Int): Int {
+    var tot = n
+    var nn = n
+    var i = 2
+    while (i * i <= nn) {
+        if (nn % i == 0) {
+            while (nn % i == 0) nn /= i
+            tot -= tot / i
+        }
+        if (i == 2) i = 1
+        i += 2
+    }
+    if (nn > 1) tot -= tot / nn
+    return tot
+}
+
+fun main() {
+    println(" n  phi   prime")
+    println("---------------")
+    var count = 0
+    for (n in 1..25) {
+        val tot = totient(n)
+        val isPrime  = n - 1 == tot
+        if (isPrime) count++
+        System.out.printf("%2d   %2d   %b\n", n, tot, isPrime)
+    }
+    println("\nNumber of primes up to 25     = $count")
+    for (n in 26..100_000) {
+        val tot = totient(n)
+        if (tot == n-1) count++
+        if (n == 100 || n == 1000 || n % 10_000 == 0) {
+            System.out.printf("\nNumber of primes up to %-6d = %d\n", n, count)
+        }
+    }
+}