[Maths-Education] Combinatorics and Sudoku

[Alan Rogerson]

It is almost trivial to write a little programme and let the computer 
work out for us all the combinatorics to enumerate all the "possible" 
sudoku grids, so in that sense the problem is neither difficult nor in a 
way interesting (especially to sudoku widows and widowers), BUT the 
complications come with the question of deciding what we regard as 
"equivalent" solutions, and thank goodness someone else has actually 
done all this hard work for us! 
Neil Pateman was kind enough to send the webapge with the answer to all 
the questions we have, but may have been afraid to ask, about sudoku 
(thanks Peter Cave for confirming the spelling and the pronunciation!). 
Here is Neil's email from Hawaii (hence the Aloha), enjoy and marvel at 
the webpage, hard work by Ed Russell and Frazer Jarvis. And yes, ther 
are no less than  5,472,730,538 "different", or as the authors put it 
more subtly:: "essentially" different, solutions.
Hi Alan:
I found a website that may prove interesting to you.
http://www.afjarvis.staff.shef.ac.uk/sudoku/sudgroup.html
Aloha,
Neil