
theorem
  2281 is prime
proof
  now
    2281 = 2*1140 + 1; hence not 2 divides 2281 by NAT_4:9;
    2281 = 3*760 + 1; hence not 3 divides 2281 by NAT_4:9;
    2281 = 5*456 + 1; hence not 5 divides 2281 by NAT_4:9;
    2281 = 7*325 + 6; hence not 7 divides 2281 by NAT_4:9;
    2281 = 11*207 + 4; hence not 11 divides 2281 by NAT_4:9;
    2281 = 13*175 + 6; hence not 13 divides 2281 by NAT_4:9;
    2281 = 17*134 + 3; hence not 17 divides 2281 by NAT_4:9;
    2281 = 19*120 + 1; hence not 19 divides 2281 by NAT_4:9;
    2281 = 23*99 + 4; hence not 23 divides 2281 by NAT_4:9;
    2281 = 29*78 + 19; hence not 29 divides 2281 by NAT_4:9;
    2281 = 31*73 + 18; hence not 31 divides 2281 by NAT_4:9;
    2281 = 37*61 + 24; hence not 37 divides 2281 by NAT_4:9;
    2281 = 41*55 + 26; hence not 41 divides 2281 by NAT_4:9;
    2281 = 43*53 + 2; hence not 43 divides 2281 by NAT_4:9;
    2281 = 47*48 + 25; hence not 47 divides 2281 by NAT_4:9;
  end;
  then for n being Element of NAT st 1 < n & n*n <= 2281 & n is prime
  holds not n divides 2281 by XPRIMET1:30;
  hence thesis by NAT_4:14;
end;
