<?php
$v = isset($_GET['v']) ? $_GET['v'] : '10';
$k = isset($_GET['k']) ? $_GET['k'] : '6';
$t = isset($_GET['t']) ? $_GET['t'] : '4';

$v = ceil($v);
$k = ceil($k);
$t = ceil($t);

$array = [1 => 41, 51, 61, 71, 81, 91, 11, 22, 33, 45];
//$licz = (count($array));
$url = "http://ljcr.dmgordon.org/show_cover.php?v=$v&k=$k&t=$t";
$content = file_get_contents($url);
$first_step = explode('<pre width=80>', $content);
$second_step = explode("</pre>", $first_step[1]);
$text = $second_step[0];

print_r($text);

$list = explode("\n", $text);
$list = preg_replace('/  /', '', $list, 1);
$string_array = preg_replace("/[[:blank:]]+/", ",", $list);
$filtered_array = array_filter($string_array);

if ($k >= $t && $v > $k && $k <= 10 && $t <= 8 && $v <= 20)
{

    foreach ($array as $a => $b)
    {
        foreach ($filtered_array as $c)
        {
            $d = explode(',', $c);
            $f = str_replace($a, $b, $d);

        }
    }
}

print_r($f);

Array
(
    [0] => 1
    [1] => 2
    [2] => 4
    [3] => 7
    [4] => 9
    [5] => 45
)