Write a PHP program where you take any positive integer n, if n is even, divide it by 2 to get n / 2. If n is odd, multiply it by 3 and add 1 to obtain 3n + 1. Repeat the process until you reach 1

<?php
function collatz_sequence($x)
{
    $num_seq = [$x];
    if ($x < 1)
    {
       return [];
    }
    while ($x > 1)
      {
       if ($x % 2 == 0)
       {
         $x = $x / 2;
       }
       else
       {
         $x = 3 * $x + 1;
       }
    # Added line
     array_push($num_seq, $x);
      }
    return $num_seq;
}
print_r(collatz_sequence(12));
print_r(collatz_sequence(19));
?>

Sample Output:

Array                                                       
(                                                           
    [0] => 12                                               
    [1] => 6                                                
    [2] => 3                                                
    [3] => 10                                               
    [4] => 5                                                
    [5] => 16                                               
    [6] => 8                                                
    [7] => 4                                                
    [8] => 2                                                
    [9] => 1                                                
)                                                           
Array                                                       
(                                                           
    [0] => 19                                               
    [1] => 58                                               
    [2] => 29   
	[3] => 88                                               
    [4] => 44                                               
    [5] => 22                                               
    [6] => 11                                               
    [7] => 34                                               
    [8] => 17                                               
    [9] => 52                                               
    [10] => 26                                              
    [11] => 13                                              
    [12] => 40                                              
    [13] => 20                                              
    [14] => 10                                              
    [15] => 5                                               
    [16] => 16                                              
    [17] => 8                                               
    [18] => 4                                               
    [19] => 2                                               
    [20] => 1                                               
)