Not sure what your question is asking. 9, 16, and 64 are perfect squares which show up a lot when using Pythagorean theorem, and are usually called "Pythagorean triplets" but they add up. Ex: 
[tex] 3^{2} +  4^{2} = 5^{2}
9 + 16 = 25   [/tex]
which is true, so (3, 4, 5) are a Pythagorean triplet.
Can you give more context to your question?