
theorem
  983 is prime
proof
  now
    983 = 2*491 + 1; hence not 2 divides 983 by NAT_4:9;
    983 = 3*327 + 2; hence not 3 divides 983 by NAT_4:9;
    983 = 5*196 + 3; hence not 5 divides 983 by NAT_4:9;
    983 = 7*140 + 3; hence not 7 divides 983 by NAT_4:9;
    983 = 11*89 + 4; hence not 11 divides 983 by NAT_4:9;
    983 = 13*75 + 8; hence not 13 divides 983 by NAT_4:9;
    983 = 17*57 + 14; hence not 17 divides 983 by NAT_4:9;
    983 = 19*51 + 14; hence not 19 divides 983 by NAT_4:9;
    983 = 23*42 + 17; hence not 23 divides 983 by NAT_4:9;
    983 = 29*33 + 26; hence not 29 divides 983 by NAT_4:9;
    983 = 31*31 + 22; hence not 31 divides 983 by NAT_4:9;
  end;
  then for n being Element of NAT st 1 < n & n*n <= 983 & n is prime
  holds not n divides 983 by XPRIMET1:22;
  hence thesis by NAT_4:14;
end;
