<?php

$page_current = 5;
$pages_total = 100;

$range_left = $page_current  - 5;
$range_right = $page_current  + 5;

if ($range_left < 1) {
    $range_right -= ($range_left - 1);
    $range_left = 1;
}
if ($range_right > $pages_total) {
    $range_left -= ($range_right - $pages_total);
    $range_right = $pages_total;
}
for($i = 1; $i <= $pages_total; $i ++) {
    if($i == 1 || $i % 10 == 0 || ($i >= $range_left && $i <= $range_right) || $i == $pages_total) {
        print($i);
    }
}