In other words: what Scott said.
]]>I am trying to find (not necessarily primitive) Pythagorean triples (a,b,c) such that a^2 = b^2 + c^2 and with c prime and odd. Using the parameterization where a=m^2 +n^2 and c =m^2 -n^2, are there necessary congruences needed for m and n?
If you try this, you will probably be reprimanded for not trying c=(m+n)(m-n) and deducing the obvious. Even without using the parameterization involving m and n, trying (a+b)(a-b)=p*p for some prime p is elementary number theory that is not quite in the scope of MathOverflow. I strongly recommend not making any more posts to MathOverflow or to meta.mathoverflow until you have made a number of successfully received posts on math.stackexchange.
Gerhard "Ask Me About System Design" Paseman, 2011.11.13
]]>