In 2001, a quantum computer was able to factor 15. In 2012, a quantum computer was able to factor 21, sorta. They cheated by not implementing gates that they knew a priori would not be used. To this day, there still hasn’t been a quantum computer to factor 21 without taking some shortcuts. Some reasons why are given here. Extrapolating from two data points is kinda ridiculous, but we only have two data points, and we’re going to do it anyway. Some may object that extrapolating the size of the nu...