จับตัวแปรมารวมกัน เพื่อวนลูป for ยังไงได้ครับผม

<?php
for($i=1;$i<=10;$i++)
{
    $sql = mysql_query("SELECT * FROM users WHERE id = '$i' order by id asc");
    $datas=mysql_fetch_array($sql );
    $username = stripslashes(str_replace('\r\n', '<br>',($datas['username'])));
    echo $name.$i = $username."<br>";
}
?>

$sql = mysql_query("SELECT * FROM users WHERE id = '$i' order by id asc");
while($datas=mysql_fetch_array($sql ){
     $k++;

      echo $result_username.$k=$datas['username']."<br>";
}

<?php
$n1 = 10;
$n2 = 100;
$n3 = 1000;

for($i = 1; $i <= 3; ++$i)
	echo ${"n$i"},"<br />";

?>