Thank you very much, good Sir! ;D I see the digits are quite important in these kinds of calculations; also a sweet bunch of new Maple tricks for my bag there.

Given a set A:={...}
and an equation 
eq1:=a^k=b^2;
eq2:=solve(%,k);

This might be what you want 8D For any set of a and b, k can only have one value

for i from 1 to nops(A) do
   for j from 1 to nops(A) do
      evalf(subs([a=A[i],b=A[j]],eq2));
      if evalb(%-round(%)=0) then
         print(k=%,[(a=A[i],b=A[j])]);
      end if;
   end do;
end do;