$conn = mysql_connect('localhost','dbusername','dbpassword') or trigger_error("SQL", E_USER_ERROR);
$db = mysql_select_db('dbname',$conn) or trigger_error("SQL", E_USER_ERROR);

for ($x = 0; $x < 106; $x++) {
   $number = rand(100,999);
   $sql = "INSERT INTO numbers (number, id) VALUES ($number, '')";
   $query = mysql_query($sql, $conn) or trigger_error("SQL", E_USER_ERROR);
}