<?
for ($i = 1; $i <= 20; $i++){
$a = rand(1,100);
echo "$a<br>";
}
?>

<?
for ($i = 1; $i <= 20; $i++){
$a = mt_rand(1,100);
echo "$a<br>";
}
?>

$arr=array();
for ($i = 1; $i <= 20; $i++) {
$a = rand(1,100);
array_push($arr, $a);
}

foreach(array_unique($arr) as $key=>$value) {
echo $value.'<br />';
}

$array = range(1, 100);
$rand_keys = array_rand($array, 20);
foreach ($rand_keys as $key) echo $array[$key] . '<br>';

$nums = range(1, 100);
shuffle($nums);
echo join("<br> ", $nums);

$rand = range(1, 100);
        shuffle($rand);
          
        
        for ($i = 0; $i <= 20; $i++) {
            echo $rand[$i] . "<br />";   
        }