[seqfan] Re: Correcting A002932 (n-step walks on square lattice)

Christopher Gribble chris.eveswell at virgin.net
Mon Nov 22 17:39:24 CET 2010

Thanks, Joseph.


-----Original Message-----
From: seqfan-bounces at list.seqfan.eu [mailto:seqfan-bounces at list.seqfan.eu]
On Behalf Of Joseph S. Myers
Sent: 22 November 2010 4:16 PM
To: Sequence Fanatics Discussion list
Subject: [seqfan] Re: Correcting A002932 (n-step walks on square lattice)

Unfortunately I don't think I'm licensed to redistribute the article
electronically.  But I don't see any sign of the lattice being bounded.  
The article describes quite a complicated method of calculating the terms
(starting from recurrences for paths where only local self-intersections /
nearest-neighbour contacts are forbidden, then subtracting terms for when
these occur at a greater distance along the path) which could well be
error-prone for higher-order terms.

Joseph S. Myers
jsm at polyomino.org.uk

On Mon, 22 Nov 2010, Christopher Gribble  wrote:

> Joseph,
> I have been working with Tom Young on a set of related problems for 
> some time.  I would be most grateful if you could send me a copy of 
> the Fisher and Hiley reference as I do not have access to it.  I think 
> that the title of A002932 may need to be made more explicit, since it 
> does not state whether the lattice is bounded or not, and, if so, what 
> form the boundary takes. Of course, no restriction on path construction is
mentioned either.
> I have calculated many cases for the general bounded lattice problem 
> with the restriction you describe.  Perhaps we can compare notes.
> Best regards,
> Chris Gribble


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