[seqfan] Re: No isosceles triangles in a square grid, continued

Neil Sloane njasloane at gmail.com
Wed Apr 27 17:18:03 CEST 2016


Ron, it is really good to have that confirmation of the first zero entry

Can you add that array too? (and tell me the A-numbers for both)

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 Wed, Apr 27, 2016 at 9:57 AM, Ron Hardin <rhhardin at att.net> wrote:

> Ok, I get something that looks right vs A271914 then I think
>
> T(n,k)=Number of nXk 0..1 arrays with exactly n+k-2 having value 1 and no
> three 1s forming an isosceles triangle
>
> Table starts
> ..1..2..3..4..5..6..7..8..9.10.11.12.13.14.15
> ..2..6.10.21.14.28.18.29.22.32.26.36.30.40...
> ..3.10.12..4.14.36.23.44.14.48.14.52.14......
> ..4.21..4..8..4.37..8.44..8.44..0.34.........
> ..5.14.14..4..4..4.10.80.37.56..4............
> ..6.28.36.37..4..8..4.22..0.34...............
> ..7.18.23..8.10..4..4..4..2..................
> ..8.29.44.44.80.22..4........................
> ..9.22.14..8.37..0...........................
> .10.32.48.44.56..............................
> .11.26.14..0.................................
> .12.36.52....................................
> .13.30.......................................
> .14..........................................
>  Note no solution for (4,11)
> rhhardin at mindspring.com rhhardin at att.net (either)
>
>
>       From: Neil Sloane <njasloane at gmail.com>
>  To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
>  Sent: Wednesday, April 27, 2016 8:43 AM
>  Subject: [seqfan] Re: No isosceles triangles in a square grid, continued
>
> No, the triangle must have nonzero area
>
> 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 Wed, Apr 27, 2016 at 8:41 AM, Ron Hardin <rhhardin at att.net> wrote:
>
> > Question, do 3 consecutive 1's in a row count as an isosceles triangle?
> > rhhardin at mindspring.com rhhardin at att.net (either)
> >
> >
> >      From: Ron Hardin <rhhardin at att.net>
> >  To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
> >  Sent: Wednesday, April 27, 2016 8:12 AM
> >  Subject: [seqfan] Re: No isosceles triangles in a square grid, continued
> >
> > Okay, good.  I should drop the "right triangle" constraint.
> >
> >
> > --
> > Seqfan Mailing list - http://list.seqfan.eu/
> >
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