Fibonacci numbers in PHP

Example for versions PHP 5.2.4, PHP 5.3.2

This example uses recursive definition of Fibonacci numbers. 

<?php
function fibonacci($n)
{
    if ($n < 3) {
        return 1; 
    }
    
    return fibonacci($n-1) + fibonacci($n-2);    
}

for ($n = 1; $n <= 16; $n++) {
    echo fibonacci($n) . ", ";
}
echo "...\n";
?>