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# User talk:Alois P. Heinz

### From OeisWiki

Dear Prof. Heinz! The page of the sequence a=A006265 consists a link to file (http://oeis.org/A006265/b006265.txt) - supposedly contributed by you - which is in the form: n a_{n-1} for n=1...500, ie. the sequence is "shifted up". Best wishes, Csaba Noszály

The b-file of A006265 is consistent with the definition and the terms which were given by N. J. A. Sloane and the formula which was given by Christian G. Bower. Look at A143897: When there are 3 leaf-nodes, we have 2 shapes. For 4 leaf-nodes only 1 shape exists, the balanced AVL tree. The b-file and the sequence are correct.

Best regards, --Alois P. Heinz 00:39, 14 March 2013 (UTC)

Dear Prof. Heinz!

Now i see, that node == leaf-node here. I computed the number of AVL trees with n
*vertices*, which is *a*_{n + 1}, and that was the cause of the trouble.

Best wishes, Csaba Noszály

Prof. Heinz, I was wondering about the formula you used for A228154/A228194. Do you have an explanation for what the variables stand for, and is there a good paper or text that covers the subject? Walt Rorie-Baety 22:47, 19 August 2013 (UTC)

Variable m is max_so_far, s is scan_max, i is length of sequence. Procedure T uses divide-and-conquer, dynamic programming and scanline paradigm. Every good book on algorithms has the details. The algorithm cannot be used to solve problem 427.

Best regards, --Alois P. Heinz 04:11, 20 August 2013 (UTC)

I have just completed an OEIS Wiki entry: "Primes of the form (a^n+b^n)/(a+b) and (a^n-b^n)/(a-b)". How does it get submitted for review?

Robert Price

## Contents |

## Offset in A000533

Hi Alois,

I posted a question about A000533 at OEIS Help Page because I am still of the opinion the sequence is not correct as given. Please feel free to share your opinion there.

Best regards,

Felix Fröhlich 14:52, 16 July 2014 (UTC)

## A123441 Number of P_4-sparse perfect graphs

Hello,

You write: "No reason to remove "perfect". Not every perfect graph is P_4-sparse". I'm not sure I understand. Not every perfect graph is bipartite either, but we're just about to mark A123408 [edited] as dead. If I read "Number of P_4-sparse perfect graphs", I would expect that not all P_4-sparse graphs are perfect, and that there's a different sequence "Number of P_4-sparse graphs". Indeed a large number of sequences from A123405 citing Hougardy: "Classes of perfect graphs" seem to have this problem. I would suggest to replace all "Number of X perfect graphs on n nodes" by "Number of X graphs on n nodes" and "Number of X Berge perfect graphs on n nodes" by "Number of X perfect graphs on n nodes", since Berge and perfect are the same and perfect is probably the more common term. - Falk Hüffner 17:08, 1 December 2015 (UTC)

## A200650

I changed the values because they are wrong. For example, a(25)=1 in the given sequence, whereas according to https://oeis.org/A200648/a200648.txt it should be 2. --Kenny Lau 03:32, 5 July 2016 (UTC)

## A272794

I created sequence A272794 and probably I made a mistake. Indeed the b-file is not correct, it provides another sequence. I want to change it, and I tried several solutions which all failed. Therefore I am enable to change it. The correct file is https://www.dropbox.com/s/hh89zzswwmkf0xi/b272794.txt?dl=0. --Pierre Lescanne 14:58, 1 August 2016 (UTC)

- Thank you. I received your mail and tried to click on
*Table of n, a(n) for n = 0..25*and I got https://oeis.org/A272794/b272794.txt whereas the correct file is https://www.dropbox.com/s/hh89zzswwmkf0xi/b272794.txt?dl=0 .--Pierre Lescanne 08:23, 2 August 2016 (UTC)

## Triangle of remainders

Professor Alois P. Heinz,

On A048158, you added the b-file Rows n = 1..141, flattened. It would be great to have a text file of the triangle with rows n = 1 to 141, especially for 2 <= k <= floor(n/2), added to the subpage Remainder/Triangle of remainders of the article Remainder article, so that we could link to it from section Remainder#Remainders triangle. It would allow to have a closer look at those remainders n mod k for k = 2 up to floor(n/2)...

It doesn't appear that knowing remainders n mod k for a small subrange of 2 <= k <= floor(n/2) would help much in finding for which k the remainder would be 0, thus finding a factorization of n... because those remainders seem to follow a really complicated pattern... I'm hinting that the subrange might have to be of the order of sqrt(n), which would not be better than trial division... — Daniel Forgues 06:27, 5 September 2016 (UTC)

## A005597

What's the problem with removing an obsolete extension, i.e., the info about the removal of a PARI program in 2010 not more matching the sequence as of today, because another PARI program was added later to A005597? –Frank Ellermann 22:21, 13 November 2017 (UTC)

We can keep that memory, no need to delete it. We also remember the removal of an incorrect g.f. or the deletion of incorrect terms, even when the correct versions are added later. - Alois P. Heinz 23:48, 13 November 2017 (UTC)

- Okay, not looking into my mail (with a clear "revert") I first assumed some obscure "delete a line" glitch in the software. –Frank Ellermann 05:32, 14 November 2017 (UTC)