p > 0 breaks this equation: a^((p-1)/2) mod p = -1 in Wolfram|Alpha

Questions
,
1

This gives me a pretty much blank page. If I remove p>0, it gives me a result. But add that in and it’s a completely blank page, other than the stuff below it like Download and Related Queries. Why??

2

What about that equation? What is given and for what are you trying to solve?

Is p supposed to be a prime?

Note tha Mathematica gives, e.g.:

      Reduce[a > 1 && Mod[a^((p - 1)/2), p] == Mod[-1, p] /. p -> 3, Integers]
C[1] \[Element] Integers && C[1] >= 0 && a == 2 + 3 C[1]

      Reduce[a > 1 && Mod[a^((p - 1)/2), p] == Mod[-1, p] /. p -> 5, Integers]
(C[1] \[Element] Integers && C[1] >= 0 && a == 2 + 5 C[1]) || (C[1] \[Element] Integers && C[1] >= 0 && a == 3 + 5 C[1])