AFAIK factoring 21 is "compiled" Shor, so even that result simplifies the problem a bit. According the first link in my post, the numbers bigger than 21 were c

AFAIK factoring 21 is "compiled" Shor, so even that result simplifies the problem a bit. According the first link in my post, the numbers bigger than 21 were chosen to have specific mathematical properties and attacked with algorithms even less realistic that compiled Shor.