Nice! How to put it in a loop? I'm totally a newbie to Lisp myself,
just gettng into Graham and Touretzky. Let's create a problem. Suppose
after excluding I want to know if the digits sum to 12, say, like maybe
they're part of a partition. S={0,..6}, S^5, excluding "*1*5*" and
"1*2*3*", say. How would I do that?