This site is supported by donations to The OEIS Foundation.

# User talk:Alonso del Arte

The bolded primes are a bit hard on the eyes. Maybe colors? I tried out a couple of ways of doing that here. Jon Awbrey 20:00, 8 January 2010 (UTC)

- Actually, I was kind of thinking that, too. Especially with the centered 11-gonal numbers. I don't have the time today to do anything about it today, so if you have the time and a neat, elegant mass replace rule, feel free to try it out. Alonso del Arte 21:46, 8 January 2010 (UTC)

- I made Wiki versions of the Regular Polygonals and the Centered Polygonals. I might try making TeX versions when I get more time. Jon Awbrey 04:08, 9 January 2010 (UTC)

- You can always just copy those tables if you want them. Jon Awbrey 22:55, 12 January 2010 (UTC)

- Of course. But now I'm not sure I really want to highlight the primes. It feels like I'm getting off topic somehow. Alonso del Arte 23:13, 12 January 2010 (UTC)

## Contents

- 1 Updating the Sequence of the Day
- 2 thanks !
- 3 Roman numerals
- 4 SoD presentation style
- 5 Notes to self
- 6 Policy
- 7 Listen to sequences
- 8 Interesting?
- 9 Memoization
- 10 Recent additions
- 11 Dragon Ball Z
- 12 Iff
- 13 Good articles
- 14 Signature permutations
- 15 Open problem (Invitation):
- 16 On the "Ordinal Sigma"
- 17 Edit at Extensions
- 18 Chase sequences
- 19 Apr 19 Seq of the Day
- 20 Backscatter
- 21 October 30, 1775
- 22 Helfgott
- 23 Some integers
- 24 Polygonal roots and oblong roots
- 25 Irrational numbers

## Updating the Sequence of the Day

I have been asked to create the SOTD, which I am happy to do. However, as I understand the current process, I have to get up tomorrow (10/18) and try to cram in my contribution before I head off to work, a hit or miss operation. That is, assuming someone else doesn't get antsy and update the SOTD page before I get to it.

It would be rather more convenient for me if I could edit my SOTD contribution at leisure, (say today, 10/17) for future posting on its day (say 10/18). Then we could have several authors create contributions ahead of time, and use them as SOTD on the most convenient day.

## thanks !

Sorry that I forgot to update this night today's SOTD with my write-up, thanks a lot for your awareness and for doing it for me! — M. F. Hasler 14:30, 3 November 2010 (UTC)

## Roman numerals

I left some supporting remarks and references for you at Talk:Roman numerals. I wasn't prepared to integrate them into the article as I'm not sure what it's trying to be, but you might want to.

Charles R Greathouse IV 07:30, 1 February 2011 (UTC)

## SoD presentation style

Do you want me from now on to style the SoD as you did on `{{ Sequence_of_the_Day_for_August_17}}`, i.e. without the extra blank lines. You seem to prefer it without blank lines, I may change my previous edits accordingly. — Daniel Forgues 20:47, 2 June 2011 (UTC)

- That is my preference, but I can't give any logical reason why my preference should be a dictum. Please take a look at User:Alonso del Arte/Test Area, try adjusting Template:Sequence of the Day according to my preferences and yours and let me know which you like better. Let's use your findings as the basis for the presentation style. (My test area page is intended to mimic what the Main Page would look like if it included the Sequence of the Day, Sequences in the News and Selected Recent Additions). Alonso del Arte 03:08, 3 June 2011 (UTC)

- If you like the spacing given by the following, I'll update the future SoD accordingly...

:{| |- style="height:30px" | <font size="5">{ 1, 2, 3, 4, 7, 6, 5, 8, 9, 10, 13, 16, ... }</font> |- |}

With style="height:30px" it's much better...

I updated `{{ Sequence of the Day for September 1}}`,

`{{`,

**Sequence of the Day for September 2**}}`{{`acordingly, what do think? — Daniel Forgues 18:47, 4 June 2011 (UTC)

**Sequence of the Day for September 3**}}- I like it. I've then also changed June 30 and July 1 accordingly. (The situation is slightly different for June 28, which shows a continued fraction, and June 29, which shows a variant of the Ulam spiral). Alonso del Arte 01:51, 5 June 2011 (UTC)

## Notes to self

"24", ",", "2016", ",", "8190", ",", "42336", ",", "45864", ",", "392448", ",", "714240", ",", "1571328" in 1139.063 seconds Alonso del Arte 23:47, 23 August 2011 (UTC)

Swenson: primes over large power of 2 & req every other bit be 0 (e.g., A002450, A000975, ) given as "strange requirements" in recital of Shannon's cryptographic principles. Alonso del Arte 08:47, 11 September 2011 (UTC)

## Policy

I made some changes to the OeisWiki:Policy page, which I split into two parts. First, some editorial changes to set a more formal tone -- not a big deal. Second, I changed the Notability example. This is in response to the recent incident with the B. polynomial pusher(s): if something like that happens again I wouldn't want the Policy page to say that they can add whatever they like.

But I thought it best if someone look over my changes lest I disturb something other than what I intended in the process. :)

Charles R Greathouse IV 06:48, 6 September 2011 (UTC)

- On a general level I have no problem with those changes. But I've never been good at predicting how people will interpret policies. Alonso del Arte 20:52, 9 September 2011 (UTC)

- You are, of course, welcome to further edit the policies if you see the need. Charles R Greathouse IV 05:15, 11 September 2011 (UTC)

## Listen to sequences

At a recent meeting njas and a few of us met to talk about the OEIS and ended up discussing ways to expand on the existing "Listen to a sequence" link on each sequence. It struck us at the time that no one in the conversation knew all that much about music, but I just realized that you might be better-palced to work with this than the person I was going to ask: you know music but also sequences. I left some mostly-coherent notes at Talk:Listen to a sequence if you have a chance.

Charles R Greathouse IV 06:22, 12 January 2012 (UTC)

## Interesting?

Here's a draft of my version: User:Charles R Greathouse IV/Imp.

Charles R Greathouse IV 04:38, 25 January 2012 (UTC)

- I hope the most relevant people see these. Alonso del Arte 15:52, 25 January 2012 (UTC)

- Once I get the bugs worked out, I intend to link to this on relevant drafts of new sequences. My real goal is to change the mindset from "I need to submit as
*many*sequences as possible" to "I need to submit the*best*sequences I can". - Charles R Greathouse IV 16:23, 25 January 2012 (UTC)
- I don't understand the former mindset at all, it's not like we're patenting genetic sequences for financial gain here. As for the latter mindset, it's quite a challenge to set an example of it because it can so easily go completely unnoticed. Alonso del Arte 16:38, 25 January 2012 (UTC)
- Yes, it's hard to come up with examples of the latter since there's subjectivity involved. Going off the keywords, not many top Klaus Strassburger for a combination of nice/total ratio and number of nice sequences. That may have something to do with his early participation, though... Charles R Greathouse IV 21:40, 25 January 2012 (UTC)

- I don't understand the former mindset at all, it's not like we're patenting genetic sequences for financial gain here. As for the latter mindset, it's quite a challenge to set an example of it because it can so easily go completely unnoticed. Alonso del Arte 16:38, 25 January 2012 (UTC)

- Once I get the bugs worked out, I intend to link to this on relevant drafts of new sequences. My real goal is to change the mindset from "I need to submit as

## Memoization

Dear Alonso, in reply to your message I now added a wiki page (stub...) on memoization. — M. F. Hasler 18:09, 25 March 2012 (UTC)

- I saw it. Looks good, better than a stub, I think. Alonso del Arte 22:06, 25 March 2012 (UTC)

## Recent additions

Alonso, I have a crazy suggestion for {{Selected Recent Additions}}. What if we set aside some fraction (a quarter, say) of the selections to come from nontraditional fields, along the lines of The multi-faceted reach of the OEIS? Of course this would not affect current choices. What do you think?

Charles R Greathouse IV 04:22, 12 July 2012 (UTC)

- I think that's a good idea. From the beginning I had wanted it to be varied, and I wanted to avoid the equivalent of how on the IMSLP the Recent Additions list would be filled by a hundred Graupner chorale harmonizations. Alonso del Arte 13:51, 12 July 2012 (UTC)

## Dragon Ball Z

You wrote [1] that Wikipedia is too unreliable for "anything besides Dragon Ball Z". But seriously, look at the context: a whole category of pages devoted to areas *outside our specialty*. Wikipedia makes us look really bad here by comparison:

- ANSI character set vs. Wikipedia:ISO/IEC 8859 or Wikipedia:Windows code page
- arXiv vs. Wikipedia:arXiv
- blogs vs. Wikipedia:blog
- not a number vs. Wikipedia:NaN
- Adrien-Marie Legendre vs. Wikipedia:Adrien-Marie Legendre
- etc.

My argument on non-math pages is that, in most cases, we'd be better off using some external resource -- yes, incuding Wikipedia -- than relying on our own pages. We don't have any special ability to write a general encyclopedia, so we should leave that task to others who do (or to other specialized encyclopedias).

I see two routes to sensible disagreement with what I have written. First, one could claim that our nonmathematical articles are of higher quality than Wikipedia's corresponding articles. Second, one could claim that, although our nonmathematical articles are not as high-quality as Wikipedia's, there are still superior free online resources to Wikipedia so much of the time so as to not even make Wikipedia worth mentioning. (I gave 7 examples of sources, so certainly this would need to happen more than 6/7 of the time to be coherent.)

Nonrhetorically, which (if either) do you believe? I'd certainly like examples.

Anecdotally, I've found a much higher percentage of errors, and of a more serious nature, here than in Wikipedia's math articles. Some of my recent edits ([2][3][4][5]) have fixed these, but there's only one me and tens of thousands of active Wikipedia editors. We *do* have mathematical articles which I would consider superior to Wikipedia's, and I certainly hope that within our narrow range of specialty we will make this the norm in coming years. But I don't think it is at present.

I don't understand your vitriol toward the site. I see it as a useful way to educate our readers about topics which may be unknown to them but which are outside our focus. Terry Tao does the same thing on his blog, so I'm not alone in feeling that way. If you have reasoned arguments to support your position I'd like to hear them, but failing that it seems like you just have an ax to grind.

Charles R Greathouse IV 03:09, 15 July 2012 (UTC)

- Maybe those Wikipedia articles were entirely correct at the time that you looked at them. Maybe they will be entirely correct when I look at them. But neither of us can keep a constant vigil on Wikipedia to make sure that only people with at least a little bit of knowledge on those topics are editing them. And if someone who doesn't know anything about math succeeds in planting a mistake in Wikipedia that stands for a long time, they can't be held accountable, whereas here on the OEIS Wiki, if someone puts in a mistake, they are accountable.
- At present I don't know of any mistake in a math article that has stood for a long time. But I will not risk getting burned, like I know so many people have gotten burned on topics other than math. Alonso del Arte 03:18, 15 July 2012 (UTC)
- P. S. I'd much rather get burned on a mistake from Peter Luschny or Daniel Forgues than Brian Chase or some anonymous teenager any day.

- I could suggest linking to the permanant version of a Wikipedia page. Would that satisfy you?
- But frankly I think your reaction is very much overblown. I see more mistakes in my print math books than I see in Wikipedia. (Sometimes I send in lists of corrections; other times, like with Yan's Number Theory for Computing textbook, I just give up... too many.) In fact the only math books I'd bet money on being more accurate word-for-word than Wikipedia would be Knuth's...
- Charles R Greathouse IV 04:25, 15 July 2012 (UTC)
- Alright, I will not complain on links to specific Wikipedia articles, whether or not it's a permanent link. With the understanding that they are vouching for that article at the time that they posted the link.
- And yes, I know math books have mistakes. We've both contributed keyword:dead sequences, haven't we? The authors of those books knew going in that mistakes could tarnish their reputations. People who plant mistakes in Wikipedia know that they'll never be called on it as long as they keep their mouths shut. Alonso del Arte 05:26, 15 July 2012 (UTC)

## Iff

I'm pretty sure I saw the usage iff (red link, I won't create the page!) in mathematical textbooks or papers... Anyway, you might like the following (see Weisstein, Eric W., Iff, from MathWorld—A Wolfram Web Resource.)

Halmos has stated, "To the best of my knowledge, I did invent the silly thing, but I wouldn't swear to it in a court of law. So there--give me credit for it anyway" (D. Asimov, pers. comm., Sept. 19, 1997).

— Daniel Forgues 01:15, 18 July 2012 (UTC)

- I've seen it, too, and if you look hard enough you can find other signs of great haste in getting the paper or book edited and typeset. Alonso del Arte 03:33, 18 July 2012 (UTC)

## Good articles

I'd like to spotlight some of our best articles here on the OEIS wiki at some point. I asked Daniel Forgues about it but he didn't respond, so I wondered if you had any ideas.

Basically I'm looking for articles which are either about the OEIS (The OEIS and its potential for expansion, User:Alonso del Arte/Is this sequence interesting) or about topics central to the OEIS (maybe prime signature, a term we apparently invented). In particular I'd like articles which are essentially the *best* resource for that piece of information, rather than one shadowing a more comprehensive article from Wikipedia/DLMF/MathWorld/MacTutor/etc. (since these are meant to promote the OEIS). Ideally they would be of general interest rather than hyper-specialized, but I could live without this in a pinch.

Charles R Greathouse IV 05:00, 18 July 2012 (UTC)

- Replied at your talk page.

- I've just seen your message. I will look for good [and non shadowing] article pages (authored by other editors). — Daniel Forgues 20:10, 20 July 2012 (UTC)

- (Of course I'd be happy to include your articles too, Daniel!) Charles R Greathouse IV 20:12, 20 July 2012 (UTC)

- Does Classifications of figurate numbers qualify? — Daniel Forgues 20:57, 20 July 2012 (UTC)

## Signature permutations

I don't understand the definition, as written, of Signature permutations. (I don't imagine it's terribly confusing, but the opening is not too clear.) Since you seem to understand it, could/would you tidy up the definition a bit?

Charles R Greathouse IV 04:47, 8 August 2012 (UTC)

- All I've been doing is taking care of certain formatting pet peeves of mine, things that we might only notice in the source but could potentially be annoying as we edit what Antti wrote. I will need to carefully look at some concrete examples of permutation signatures before I can do anything to clarify the definition. Alonso del Arte 03:46, 9 August 2012 (UTC)

- Now I added there a formal definition, which includes a link to a new page Ranking and unranking functions. Please tell me if it's still obscure! Unfortunately, it's difficult for me to avoid using neologisms I have invented (such as "global ranking function", in contrast to ordinary "ranking function" that already occurs in the literature) when explaining things. (But fortunately, OEIS Wiki doesn't explicitly forbid "original research" as the Wikipedia does, or am I right? ;-) Also, I think we need a Wikipedia-like definition for total ordering. I opened a comment on that at Talk:Orderings. And sorry guys if it feels that I leave a formatting mess for you to clean up, I'll try to improve my editing habits! Antti Karttunen 13:38, 9 August 2012 (UTC)

- Part of it is that I didn't know you were editing on a phone. I don't mind doing formatting edits like that, but I can't always devote enough time to the task and leave it halfway done. Regardless of whether or not I had finished that particular one, I don't really need or want credit because, aside from moving the definition closer to the top, my edits only affected the source. Alonso del Arte 16:57, 9 August 2012 (UTC)

## Open problem (Invitation):

Given an integer N>0, and after been found all the first N! terms of A217626, you were asked find either a function or algorithm which counts the number of different "trivial" palindromic patterns that could be built from these terms.

For example:

[1,9,2,9,1] is a "trivial" palindromic pattern.

But

[2,18,4,18,2] is not trivial, until it is re-written it as: [2,2*9,4,9*2,2]

So the "triviality" of such kind of patterns depends on the prime factorization of their components. Such behavior can not be reproduced by the prime numbers.

I can not spot it yet "the how", but the study of this matter might have deep implications in the number theory. (These patterns teach us how to build odd numbers in a similar way as what described by the Goldbach's Conjecture for the even numbers).

If you decide to face this friendly challenge,

Good Luck!!!

Sincerely, with regards:

R. J. Cano 18:56, 15 December 2012 (UTC)

## On the "Ordinal Sigma"

Reply: [[My humble opinion and viewpoint based on my own works][File:http://www.oeis.org/w/images/9/99/Reply01-mrAlonso.pdf]]

All the best professor.

R. J. Cano 19:21, 17 December 2012 (UTC)

- I'm not a professor, but thank you very much for your consideration of my little problem. Your problem seems to be more interesting, but it also requires a lot more study and reflection, so I'm not likely to have any insights into it just yet. Alonso del Arte 00:34, 21 December 2012 (UTC)

Dear Alonso.

Well, after some time re-thinking these matters, Fortunately I was able to improve a little my published content at A215940, A211869, and A217626, from a Linear Algebra approach.

These were nice times beyond the remaining parts in the day-to-day living of a mortal.

I wish you health, success and good luck. Like Mr. Spoke would say "Live long and prosper".

Sincerely,

R. J. Cano, On Jun 26th 2014 19:59 VET.

Note: Please forgive me for calling you "professor", just you made me recall due your name a good Maths teacher who taught me basic Algebra at secondary school (Mr. A. Fernandez); Just that.

Thank you. Alonso del Arte 01:43, 29 June 2014 (UTC)

## Edit at Extensions

See [6] and ping me if you disagree.

(Merry Christmas/happy holidays/etc.)

Charles R Greathouse IV 20:20, 26 December 2012 (UTC)

## Chase sequences

I've finished the draft of a new essay, tentatively living at User:Charles R Greathouse IV/Chase sequences. If you have a chance to look it over and give feedback it would be appreciated.

My idea is to describe a problem and what can be done about it, but in a sufficiently nonconfrontational way that authors won't take offense. Of course the idea is that this will actually improve sequences, which is good for the authors...

As a separate issue, I found it necessary to give a concrete example. Of course I don't want to offend the author either! He's one of our good contributors, though, and I don't expect this will be a problem (unless you think I need to make changes).

Charles R Greathouse IV 07:03, 4 January 2013 (UTC)

- He's probably the best choice for the concrete example, others would be either very offended or very oblivious. Alonso del Arte 18:49, 4 January 2013 (UTC)

## Apr 19 Seq of the Day

I can review/approve, sure. Possibly the entry should be edited to reflect that the conjecture is true?

Charles R Greathouse IV 07:04, 6 April 2013 (UTC)

## Backscatter

Do you know what the OEIS reference was in that episode? Might be worth adding.

Charles R Greathouse IV 16:00, 28 April 2013 (UTC)

- I didn't watch it when it aired, but apparently I can watch it right now for free by clicking a link on the episode's IMDB page. Alonso del Arte 18:52, 28 April 2013 (UTC)

## October 30, 1775

You wrote:

- Benjamin Franklin publishes an essay on the usefulness of mathematics in the Pennsylvania Gazette.

Do you happen to have a copy? I couldn't find anything online. Of course the article is in the public domain... in fact it predates copyright (which dates to 1784 in Pennsylvania and 1790 in the US).

Charles R Greathouse IV 13:40, 14 August 2013 (UTC)

- [Replied at your talk page].

## Helfgott

The article for the Goldbach conjecture links two Helfgott papers. I think if we ask Helfgott himself, he'd be quite happy to have just the links to his papers, and not a link to a Wikipedia page which could potentially be used to spread lies about him. See <http://wikipediocracy.com/2013/05/17/anonymous-revenge-editing-on-wikipedia-the-case-of-robert-clark-young-aka-qworty/>. Alonso del Arte 04:20, 17 May 2014 (UTC)

- as you wish--Bill McEachen 01:07, 20 May 2014 (UTC)

## Some integers

Template:Some integers seems to include i and -i, why is that? They're Gaussian integers, but not integers. Charles R Greathouse IV 16:22, 1 April 2015 (UTC)

- I was unsure whether also to include a link to the algebraic integers article. Maybe better not, so for now I've also commented out and . Alonso del Arte 03:49, 2 April 2015 (UTC)

## Polygonal roots and oblong roots

See polygonal roots and oblong roots. — Daniel Forgues 03:31, 26 June 2015 (UTC)

- I'm sorry, I don't have anything to fill that second page with. Alonso del Arte 16:50, 28 June 2015 (UTC)

- Oops! The second page was meant to be a redirect. I fixed it. Now you may have a look! — Daniel Forgues 00:34, 29 June 2015 (UTC)

## Irrational numbers

I saw that you removed some (poorly-written) "text of uncertain veracity" in Irrational numbers. I added some content there about Hurwitz's theorem, which I think is what the old text was trying to get at. Does it look good to you?

Charles R Greathouse IV 17:52, 14 March 2016 (UTC)

- I did mostly presentational edits, e.g. HTML+CSS [inline] text style mathematics with the
`{{math}}`template. You say: 'you removed some (poorly-written) "text of uncertain veracity"'. I looked through the history of the page: this was done by Alonso del Arte. — Daniel Forgues 00:36, 16 March 2016 (UTC)

- The page looks good to me. — Daniel Forgues 00:44, 16 March 2016 (UTC)

- Yes, I removed that text. Speaking only for myself, I'm okay with text of such great uncertainty ("is it true?" appeared several times in it) being in an unreviewed draft after a stable version. But in this particular case, there was no stable version to begin with. Alonso del Arte 03:18, 16 March 2016 (UTC)

- Yes Daniel -- I was talking to Alonso when I wrote that. :) Alonso: hopefully this gives you a reasonable stable version to start from. Charles R Greathouse IV 13:21, 16 March 2016 (UTC)

- I should have mentioned that I added many things in the two consecutive edits

- and then I added those many "(IS IT TRUE?)" in the following edit

- because I couldn't find something online (to link to) to corroborate what I had just added. I wanted someone else to ascertain the truth (or falsehood?) of what I had written. — Daniel Forgues 16:22, 16 March 2016 (UTC)

- See Talk:Irrational numbers#The higher the degree of an algebraic number, the faster the sequence of convergents converges. — Daniel Forgues 16:30, 16 March 2016 (UTC)

- I admit that some of my text on irrational numbers was really poorly-written (and even wrong, which I was afraid of, and thus had it flagged with "is it true?"). I completely rethought and rewrote my text on Talk:Irrational numbers. — Daniel Forgues 22:35, 16 March 2016 (UTC)