[seqfan] Re: Peaceable queens: a new sequence and a possible omission in A250000

[Neil Sloane]

By the way, A000170, the number of solutions to the classical problem,
gives only one example.  Could anyone supply complete sets of solution for
small n?

(This won't help with the Peaceable Queens problem, since for n>4 the
numbers are different - the Peaceable version has more queens on the board.)


Best regards
Neil

Neil J. A. Sloane, President, OEIS Foundation.
11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
Phone: 732 828 6098; home page: http://NeilSloane.com
Email: njasloane at gmail.com



On Sun, Mar 17, 2019 at 4:24 PM Neil Sloane <njasloane at gmail.com> wrote:

> In other words, take 4 classically non-attacking queens
>
> +---------+
>
> | . Q . . |
>
> | . . . Q |
>
> | Q . . . |
>
> | . . Q . |
>
> +---------+
>
> and change two of them to black queens and two to white queens
> and that would be two solutions for Peaceable Queens that are not listed
> in A250000.
> There are two ways because the black Q's could be opposite or adjacent.
>
> Yes, I agree!  Rob, is this going to affect the other counts of different
> solutions that you made?
>
>
> On Sun, Mar 17, 2019 at 4:04 PM Benoît Jubin <benoit.jubin at gmail.com>
> wrote:
>
>> Hi Seq Fans,
>>
>> In the EXAMPLE field of A250000 (peaceable queens), it is written that for
>> n=4, there are 8 inequivalent configurations (and they are pictured).
>> Aren't there two more coming from the configuration of 4 non-attacking
>> queens on a 4 X 4 chessboard?  This would imply that A260680(4)=10 and not
>> 8.
>>
>> On a related note, I just submitted A306954, which generalizes A250000 to
>> the case of k armies on the n X n chessboard.  Computer programs should
>> easily give some more terms.
>>
>> Best regards,
>> Benoît
>>
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>>
>