[seqfan] Re: sequences with regularity for rather large n

Vladimir Shevelev shevelev at bgu.ac.il
Fri Nov 29 14:53:18 CET 2013

As an example, see A232636: "The second largest value of permanent on (0,1) square matrices of order n>=30 with row and column sums 3". 
Strictly speaking, all terms of A232636 are conjectural since my method is based on the following very plausible  but yet not proved conjecture with confirms in many cases and no any counter-example beginning with 1992( when I posed it). Let L_n be set of nxn (0,1)-matrices with all row and column sum 3. Let S_n be subset of completely indecomposable such matrices, i.e., not containing submatrices from L_m (m<n). Let
M(n) be the maximal value of permanent on S_n. Then M(n_1+n_2)<=M(n_1)*M(n_2).
I did not this in comment, since  refered to my link, but now I did that.
Maybe, indeed, I submitted this sequence into OEIS early. I simply wanted to tell the readers, using this sequence, about difficult problems arising  in theory of permanents in even rather simple structure of matrices.


From: SeqFan [seqfan-bounces at list.seqfan.eu] on behalf of Alonso Del Arte [alonso.delarte at gmail.com]
Sent: 29 November 2013 01:49
To: Sequence Fanatics Discussion list
Subject: [seqfan] Re: sequences with regularity for rather large n

I too would like an example.

But just based on what you've said, I would say go for it. In your case,
almost any Editor would get the sense that you have genuinely made an
effort to ascertain what a(29) is but for the time being it's just not
possible. Let's further suppose that for n < 30 there are so many holes you
can't string along more than two or three consecutive known terms. The
offset of 30 makes perfect sense.


P.S. Today is Thanksgiving in the U. S., and for a few more minutes the
Sequence of the Day is

A000055 <http://oeis.org/A000055>: Number of trees with [image:
\scriptstyle n,\, n \,\ge\, 0, \,] unlabeled nodes.
  { 1, 2, 3, 6, 11, 23, 47, 106, 235, ... }  This is the sequence for the
example search on the front page of the OEIS <http://oeis.org/wiki/OEIS>.
This Thanksgiving we are thankful for, among other things, the OEIS, which
is an invaluable resource in many mathematical and scientific endeavors.

On Thu, Nov 28, 2013 at 12:35 PM, John W. Nicholson
<reddwarf2956 at yahoo.com>wrote:

> Can you give an example?
> John W. Nicholson
> On Wednesday, November 27, 2013 4:40 AM, Vladimir Shevelev <
> shevelev at bgu.ac.il> wrote:
> Dear seqfans,
> >
> >I met with a problem. I know interesting sequences the regularity of
> which begins
> >with, say, n=30, but for n<30 not all its terms are known and what is
> more are
> >very difficult calculated using even modern computers. Can I use offset 30
> >and in comment to explain the problem? Or it is not suitable for OEIS?
> >
> >Best regards,
> >Vladimir
> >
> >_______________________________________________
> >
> >Seqfan Mailing list - http://list.seqfan.eu/
> >
> >
> >
> _______________________________________________
> Seqfan Mailing list - http://list.seqfan.eu/

Alonso del Arte
Author at SmashWords.com<https://www.smashwords.com/profile/view/AlonsoDelarte>
Musician at ReverbNation.com <http://www.reverbnation.com/alonsodelarte>


Seqfan Mailing list - http://list.seqfan.eu/

More information about the SeqFan mailing list