Initial data commit

Task/Mutual-recursion/C-sharp/mutual-recursion.cs

@@ -0,0 +1,21 @@
+namespace RosettaCode {
+    class Hofstadter {
+        static public int F(int n) {
+            int result = 1;
+            if (n > 0) {
+                result = n - M(F(n-1));
+            }
+
+            return result;
+        }
+
+        static public int M(int n) {
+            int result = 0;
+            if (n > 0) {
+                result = n - F(M(n - 1));
+            }
+
+            return result;
+        }
+    }
+}