Fibonacci序列 - PHP最短代码(Fibonacci Sequence - PHP shortest code possible)

 我花了一些时间尝试将Fibonacci序列执行到500个数字并以尽可能短的代码输出到屏幕。 这对我来说是一次学习练习。 
 
 我把它从21行压缩到12行，这是我能编写的最短代码，这使得这个工作..任何人都可以告诉我如何使代码更短？ 
 
 我已经在google上查找了PHP循环，而while循环似乎效果最好。 PHP中是否还有其他数学技巧可以用来压缩这个？ 
 
 通常当我问一个问题时，我喜欢展示我对这个问题所做的研究，但由于我不知道任何关键字要查找更好的数学或循环，我不知道该搜索什么... 
 
 码： 
 
$counter = 0;
$first = 1;
$second = 1;
echo $first."<br/>";
echo $second."<br/>";
while ($counter < 500) {
  $next = $first + $second;
  echo $next."<br/>";
  $counter++;
  $second=$first;
  $first=$next;
}

I have spent some time trying to execute the Fibonacci sequence to 500 numbers and output to screen in the shortest amount of code possible. This was a learning exercise for me.
 
I have condensed it from 21 lines down to 12, this is the shortest code I can write that makes this work.. Can anyone show me how I could have made the code even shorter?
 
I have looked on google for PHP loops, and the while loop seemed to work best. Are there any other math tricks in PHP I can use to condense this even more?
 
Normally when I ask a question, I like to show what research I have done into the problem, but since I don't know any keywords to look up for better math or loops, I am not sure what to search.. 
 
Code:
 
$counter = 0;
$first = 1;
$second = 1;
echo $first."<br/>";
echo $second."<br/>";
while ($counter < 500) {
  $next = $first + $second;
  echo $next."<br/>";
  $counter++;
  $second=$first;
  $first=$next;
}

原文：