diff --git a/jolt-core/clojure/core/20-coll.clj b/jolt-core/clojure/core/20-coll.clj
index 91b30ab..d201fda 100644
--- a/jolt-core/clojure/core/20-coll.clj
+++ b/jolt-core/clojure/core/20-coll.clj
@@ -209,16 +209,8 @@
 (defn rationalize [x] x)
 
 ;; trampoline: repeatedly calls f with args until a non-function result.
-(defn trampoline
-  ([f] (trampoline f (f)))
-  ([f & args]
-   (let [ret (apply f args)]
-     (if (fn? ret)
-       (recur ret)
-       ret))))
 
 ;; rand-int: random integer in [0, n). Uses Janet math/random.
-(defn rand-int [n] (math/floor (* (math/random) n)))
 
 ;; Eager dedupe of consecutive equal elements (Jolt has no transducer arity yet).
 (defn dedupe [coll]
diff --git a/src/jolt/core.janet b/src/jolt/core.janet
index 19b4c03..3eb75be 100644
--- a/src/jolt/core.janet
+++ b/src/jolt/core.janet
@@ -1405,6 +1405,10 @@
 
 
 (defn core-rand-int [n] (math/floor (* (math/random) n)))
+(defn core-trampoline [f & args]
+  (var result (apply f args))
+  (while (function? result) (set result (result)))
+  result)
 (def core-format (fn [fmt & args] (string/format fmt ;args)))
 
 # ============================================================