diff --git a/Number Theory/Catalan_number.cpp b/Number Theory/Catalan_number.cpp
index ca828d4..85d50b7 100644
--- a/Number Theory/Catalan_number.cpp	
+++ b/Number Theory/Catalan_number.cpp	
@@ -20,6 +20,11 @@ int catalanNumber( int n ){
 	return dp[n];	
 }
 
+/*
+	Formula for Catalan Number
+	(2n-C-n)/(n+1)
+*/
+
 int main(int argc, char* argv[] ){
 
 	cout << catalanNumber(3) << '\n';