Contoh Program Rekursif

<?php

// from 1, step to 3, until 100
fib(1, 3, 100);

function fib($a, $b, $n){
echo $a. "   ";
$c = $a + $b;
$a = $b;
$b = $c;
if ($a <= $n) {
return fib($a, $b, $n);
}
}