the following floated to my mind today, can you verify if it stands to be true, or is a pre-existing conjecture. If not, can you correct me? And if it is one, can you prove it?
Prime factorisation of any perfect square $P$ of the form
$$P=a_1^{x_1}\times a_2^{x_2}\times a_3^{x_3}\times.........\times a_n^{x_n} $$ where $$x_1,x_2≠0$$ which implies that atleast two non unity factors exist,then $$a_1^{x_1}+ a_2^{x_2}+ a_3^{x_3}+.........+ a_n^{x_n}=Z$$ where $Z$ is perfect square, is only applicable for $P=144$.
Example: for $P=144$, prime factorisation is as follows: $$2^4\times 3^2$$ and $$2^4+ 3^2=25=5^2$$
There are many solutions.
This PARI/GP program searches for solutions :