diff --git a/include/real/real_math.hpp b/include/real/real_math.hpp
index 15012a7..314a6c2 100755
--- a/include/real/real_math.hpp
+++ b/include/real/real_math.hpp
@@ -360,9 +360,7 @@ namespace boost{
 				else 
 					result -= cur_term;
 				
-				for(exact_number<T> i = (two * term_number) + literals::one_exact<T> ; i <= two * (term_number + literals::one_exact<T>); i = i + literals::one_exact<T>){
-					factorial *= i;
-				}
+				factorial *=((two * term_number) + literals::one_exact<T>)*(two * (term_number + literals::one_exact<T>));
 				cur_power *= square_x;
 				cur_term = cur_power;
                 ++ term_number_int;