Print Fibonacci Sequence/Series

Below program will generate the Fibonacci sequence/series up to a given number:

<?php

// print fibonacci series
function printFibonacciSeries($number) 
{
    $series = 0;
    $increment = 1;

    echo "Fibonacci Series of $number: ";

    for ($i = 0; $i < $number; $i++) {
        echo $series . " ";

        $nextNumber = $series + $increment;
        $series = $increment;
        $increment = $nextNumber;
    }
}

$number = 10;

printFibonacciSeries($number);

?>

Result:

Fibonacci Series of 10: 0 1 1 2 3 5 8 13 21 34