The "robbins" forum (formerly known as the "bilinear" forum) is a 
mailing-list for people studying sequences and arrays satisfying 
various sorts of non-linear recurrence relations (e.g., Somos 
sequences), and the combinatorial objects that these sequences 
and arrays enumerate (e.g., tilings).

These recurrence relations a priori should give rise to fractions 
(more generally, rational functions) but via mysterious cancellations 
they give rise to integers (more generally, Laurent polynomials).

The forum is named in honor of David Robbins, whose work on Dodgson 
condensation and alternating-sign matrices provided much inspiration 
for this research.

Only authorized members of the robbins forum can submit postings.  
To subscribe to the forum, send email to propp at jamespropp dot
org.

Anyone can read the archive, subject to the following proviso: 
Postings sent to robbins should not be forwarded to other people 
or forums without the permission of the individuals who posted the 
messages.  AND, when such forwarding is done, you must strip out 
the string "<address-of-forum>@cs.uml.edu" from the header 
(where <address-of-forum> = "dr" followed by "12742", in tribute 
to DR's 1991 article "The story of 1, 2, 7, 42, 429, 7436, ...").  

Please don't forget to strip out this string in anything you
post to the web, or forward to anyone who might inadvertently
post it!  Otherwise, the email address of the forum will become 
available to spammers.

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* Please help us avoid spam-attacks on our forum by NOT putting the email *
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The archive of past postings to the forum is accessible via
	http://jamespropp.org/robbins/archive
To access this file, you will need to enter the username "robbins" and 
the password "david".  You may not copy the archive file.

If you like this forum, you might also like the _domino_ forum (see
http://jamespropp.org/about-domino).

The Somos sequence web-page 
	http://jamespropp.org/somos.html
has material that may be of interest to many readers to the forum.

Jim Propp
Department of Mathematics
University of Massachusetts Lowell
July 25, 2007