<?php
function toBase($num, $b=62) {
$base='0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$r = $num % $b ;
$res = $base[$r];
$q = floor($num/$b);
while ($q) {
$r = $q % $b;
$q =floor($q/$b);
$res = $base[$r].$res;
}
return $res;
}
function to10( $num, $b=62) {
$base='0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$limit = strlen($num);
$res=strpos($base,$num[0]);
for($i=1;$i<$limit;$i++) {
$res = $b * $res + strpos($base,$num[$i]);
}
return $res;
}
for ($i = 0; $i<5000; $i++) {
$x = toBase($i);
$y = to10($x);
echo "\n$i -> $x -> $y";
}