I saw that one of the interview questions could be building a pascal triangle. Is there anything wrong with this particular solution I came up with?

function pascal_r($r){

   $local = array();

   if($r == 1){
       return array(array(1));
   } else {
       $previous = pascal_r($r - 1);

       array_push($local, 1);

           for($i = 0; $i < $r - 2 && $r > 2; $i++){
               array_push($local, $previous[$r-2][$i] + $previous[$r-2][$i + 1]);
           }

       array_push($local, 1);
   }

   array_push($previous, $local);

   return $previous;

}

print_r(pascal_r(100));