Permutations

[Marc LeBrun]

 >=Eric W. Weisstein
 >>=Christopher Tomaszewski
 >> Here are all 24 permutations of {1,2,3,4}, with those satisfying my
 >> criteria in red:
 > There is no such thing as red in email...

This point is well-taken, eMail ought always support the least common 
denominator.  On the other hand that appears likely to become HTML...

Sneaky Advertisement Dept.: You may recall my "numbral" notation for 
general "object oriented arithmetic", where you write just [n] for the n-th 
whatever, understood from context.  This originated as a way to ASCIIfy 
"The Book of Numbers"'s convention of printing numbers in black and 
"nimbers" in red.  Don Knuth cleverly christened those []s the "red shift" 
operator!  So I guess if you really want red in eMail, you can use this 
notation!  (RKG: Did the authors of BoN and WW do anything like this?  Or 
did you just use colored pens in manuscript?)