7.1.22  Solving a²+b²=p in ℤ

Any prime number congruent to 1 modulo 4 can be written as a sum of two squares. The pa2b2 command finds such a decomposition.

• pa2b2 takes p, a prime number which is congruent to 1 modulo 4.
• pa2b2(p) returns a list of integers [a,b], where p=a²+b².

Example

indeed, 17=4²+1².