I like the description of graham&#x27;s number (by graham) using the up-arrow notation <a href="https:&#x2F;&#x2F;youtu.be&#x2F;GuigptwlVHo?t=31" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;GuigptwlVHo?t=31</a>