function factor_post_counts($x,$times='×') {
$f=array();
$i=3;
$x||$x=1;
$x==1&&$f[]=1;
while($x%2==0){$f[]=2;$x/=2;}
while($i*$i<=$x){$x%$i?$i+=2:($f[]=$i)&&($x/=$i);}
$x>1&&$f[]=$x;
return implode($times,array_map(function($v,$k){return $v>1?$k.'[sup]'.$v.'[/sup]':$k;},$a=array_count_values($f),array_keys($a)));
}
echo factor_post_counts($post[posts]);