Prints fibonacci sequence based on $numbersToShow starting from $startNumber

fibonacci.php

<?php

error_reporting(E_ALL);
ini_set('display_errors', true);

// 0, 1, 1, 2, 3, 5, 8, 13, 21, 34

$startNumber = 0;
$numbersToShow = 10;

function fibonacci($number)
{
    if ($number === 0) {
        return 0;
    } elseif ($number === 1) {
        return 1;
    } else {
        return (fibonacci($number-1) + fibonacci($number-2));
    }
}

for ($i = $startNumber; $i < ($startNumber+$numbersToShow); $i++) {
    echo fibonacci($i).PHP_EOL;
}