diff --git a/app.js b/app.js
index bba68419..ad671cd9 100644
--- a/app.js
+++ b/app.js
@@ -1,12 +1,13 @@
 'use strict';
 const memo = new Map();
 memo.set(0, 0);
-memo.set(1, 1);
+memo.set(1, 0);
+memo.set(2, 1);
 function trib(n) {
     if (memo.has(n)) {
         return memo.get(n);
     }
-    const value = trib(n - 1) + trib(n - 2);
+    const value = trib(n - 1) + trib(n - 2) + trib(n - 3);
     memo.set(n, value);
     return value;
 }