I guess it depends what you mean by "factored" and "quantum computer" -using the generally accepted definitions, the number 15 has never been factored on a quantum computer using the Shor algorithm.
Yes, I am talking about the general case where you don't leave out the gates for 2 and 7 being factors of 15. That's what most people mean by factoring. Stating the answer because you know it already isn't useful. LARPing by running the algo through the "right" gates also isn't useful.