Squares with squares Are there a group of numbers whose squares are made up of squares? For example, $7$ would be one because $7^2$ is $49$ which has $2^2$ and $3^2$. $20$ would be another example.

What are these numbers called?

Please help me find good tags for this question.
OEIS calls them Numbers whose square is a nontrivial concatenation of other squares, and calls the sequence of their squares Squares which are a decimal concatenation of two or more squares. One of the references from that latter sequence calls the squares Smarandache square-partial-digital [numbers].
I am not agree with taking $20$ as a number of that kind ( or trivial in whose case $10, 30,40,50,60,70,80,90$ are too). 

We show here that the only two-digit number with four-digit square of this kind is $41$. Looking at the algorithm of extraction of the square root in the figure below we can write



$$ab=x^2\Rightarrow 4\le x\le 9$$
$$y(20x+y)=cd=z^2\Rightarrow y(20x+y)\le 81\Rightarrow x=4$$

Hence $$y(80+y)\le81\Rightarrow y=1$$
No other possibility. In fact $41^2=1681$ as we wished.