List the perfect squares between 100 and 500 that are even numbers

 Find the total number of perfect squares in numbers between 100 to 500
Let’s start with 100
=> 10 x 10 = 100
=> 11 x 11 = 121
=> 12 x 12 = 144
=> 13 x 13 = 169
=> 14 x 14 = 196
=> 15 x 15 = 225
=> 16 x 16 = 256
=> 17 x 17 = 289
=> 18 x 18 = 324
=> 19 x 19 = 361
=> 20 x 20 = 400
=> 21 x 21 = 441
=> 22 x 22 = 484
Thus, the total perfect square found in numbers between 100 to 500 is 13.

Where are the following equations?