example from comfusy, still with pattern matching

testcases/synthesis/PrimeHeuristic.scala

+import leon.Utils._
+
+object PrimeHeuristic {
+  def maybePrime(n: Int): Boolean = n match {
+    case 2 * k     => false
+      case 3 * k     => false
+      case 6 * k - 1 => true
+      case 6 * k + 1 => true
+  }
+
+}