diff --git a/src/mortgage/core.cljs b/src/mortgage/core.cljs
index f634374..35793d9 100644
--- a/src/mortgage/core.cljs
+++ b/src/mortgage/core.cljs
@@ -69,7 +69,7 @@
      (* (:num-years m)
         12)))

-(sm/defn get-payments :- [MonthlyPayment]
+(sm/defn -get-payments :- [MonthlyPayment]
   [m :- Mortgage]
   (loop [principal (get-loan-amount m)
          result []]
@@ -86,6 +86,8 @@
                (conj result payment)))
       result)))

+(def get-payments (memoize -get-payments))
+
 (sm/defn full-monthly-payment-amount :- s/Num
   [m :- Mortgage]
   (->> m