wiki: about Fibonacci number

https://en.wikipedia.org/wiki/Fibonacci_number

PHP array:

http://php.net/manual/en/language.types.array.php

PHP for loop:

http://php.net/manual/en/control-structures.for.php

PHP functions:

http://php.net/manual/en/function.print-r.php http://php.net/manual/en/function.array-push.php http://php.net/manual/en/function.end.php