How can I print integer in triangle form

Question

I want to print integer in triangle form which look like this

    1
   121
  12321

I tried this but I do not get the actual result

Answer 1

A little late to the party, but here's yet another solution that uses a "for" loop with two initialization variables and a ternary-based incrementer/decrementer. It's an unorthodox use of a "for" loop, but it's still perfectly valid and arguably makes the code more elegant and easier to follow. I chose to add space before and after each semicolon and omit all other space inside the parentheses so it's easier to visualize each of the three pieces of the "for" loop (initialization, condition, increment/decrement):

$count = 9;
echo "
";
for ($i=1; $i<=$count; $i++) {
    echo str_pad("",$count-$i," ",STR_PAD_LEFT);
    for ( $j=1,$up=true ; $j>0 ; $up?$j++:$j-- ) {
        echo $j;
        if ($j==$i) {$up = false;}
    }
    echo "
";
}
echo "
";

Output:

        1
       121
      12321
     1234321
    123454321
   12345654321
  1234567654321
 123456787654321
12345678987654321