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

[Neil Sloane]

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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