MathPHP\Sequence\Basic::factorial PHP Метод

    public static function factorial(int $n) : array
    {
        if ($n <= 0) {
            return [];
        }
        $factorial = [1];
        if ($n === 1) {
            return $factorial;
        }
        for ($i = 1; $i < $n; $i++) {
            $factorial[] = $i * $factorial[$i - 1];
        }
        return $factorial;
    }