MathPHP\Sequence\Basic::arithmeticProgression PHP Метод

    public static function arithmeticProgression(int $n, int $d, int $a₁) : array
    {
        if ($n <= 0) {
            return [];
        }
        $progression[1] = $a₁;
        for ($i = 1; $i < $n; $i++) {
            $progression[$i + 1] = $progression[$i] + $d;
        }
        return $progression;
    }