Data update

Task/Totient-function/Julia/totient-function.jl

@@ -0,0 +1,18 @@
+φ(n) = sum(1 for k in 1:n if gcd(n, k) == 1)
+
+is_prime(n) = φ(n) == n - 1
+
+function runphitests()
+    for n in 1:25
+        println(" φ($n) == $(φ(n))", is_prime(n) ? ", is prime" : "")
+    end
+    count = 0
+    for n in 1:100_000
+        count += is_prime(n)
+        if n in [100, 1000, 10_000, 100_000]
+            println("Primes up to $n: $count")
+        end
+    end
+end
+
+runphitests()