6.4 (up to just before section 6.4.1), due on October 22

1. (Difficult) I think the (p-1) factoring method was a little difficult to follow.  Does B! mean B factorial, or does that have some other meaning?  It also was not clear to me n can be factored if both p-1 and q-1 have small factors.
2. (Reflective) I thought the construction for finding a large n that avoids this attack was clever, I don't know if I've ever seen that before.
   I do recall having to be careful about p-1 before, (possibly when making an implementation of RSA?) but I don't think I knew (or at least) remember why.  Although I don't know if I understand especially well now, I think with more thought and perhaps some help, I could.