theorem
  16 satisfies_Sierpinski_problem_86
  proof
    reconsider a = 3 as Prime by XPRIMES1:3;
    reconsider b = 5 as Prime by XPRIMES1:5;
    reconsider c = 17 as Prime by XPRIMES1:17;
    take a,b,c;
    thus thesis by Th55;
  end;
