diff --git a/config.json b/config.json
index 41e0e3a..e3a670d 100644
--- a/config.json
+++ b/config.json
@@ -320,6 +320,15 @@
       "difficulty": 1,
       "topics": [
 
+      ]
+    },
+    {
+      "slug": "collatz-conjecture",
+      "core": false,
+      "unlocked_by": null,
+      "difficulty": 1,
+      "topics": [
+
       ]
     }
   ],