<?php
$text   = "1*10
11*20
21*30
31*40
41*50";
$textAr = explode("\n", str_replace("\r", "", $text));
$textAr = array_filter($textAr, 'trim');
 
foreach ($textAr as $line) {
    $pieces = explode("*", $line);
    list($first, $last) = array_pad(explode('*', $line, 2), 2, null);
 
    $add = 1;
    for ($i = $first; $i <= $last; $i += $add) {
        $array[] = array(
            'count' => $i
        );
    }
 
 
}
 
$codes = $array;
foreach ($codes as $code) {
    echo $code['count'];
    echo "<br>";
}

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