Supporting or illustrative mini-web-apps?

[Allan Wechsler]

I don't remember if we consider it appropriate to upload to OEIS a small web-app that provides illustration of a sequence, or enables calculation of sequence elements.

The kind of app I have in mind would require no server support after the user actually displays it in a browser -- all the code runs locally on the browser.

I ask because I recently set up a web-app whose purpose is to explore oeis.org/A147680 ("disk polyominoes"). I have been having fun playing with it locally, and thought maybe others might like it too. But if this kind of thing is considered appropriate, I should spend some time adding documentation.

The .html file in question is 400 lines long, about 15K bytes.

-- Allan

[Charles Greathouse]

I think that’s completely appropriate, but I haven’t tested if it works (whether it allows that extension and whether it serves it as the right MIME type etc.), but it’s probably easier to just try it than figure that out otherwise.

If Sean has any additional information or corrections I’m sure he’ll stop by to let us know.

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[Neil Sloane]

I'm all in favor of that kind of web app, as long as Russ and Sean have no objections (there may be security issues we don't know about)

Best regards

Neil 

Neil J. A. Sloane, Chairman, OEIS Foundation.

Also Visiting Scientist, Math. Dept., Rutgers University, 

Email: njas...@gmail.com

On Thu, Jun 4, 2026 at 4:41 PM Allan Wechsler <acw...@gmail.com> wrote:

--

[Sean A. Irvine]

I certainly have no objections.

I know such things will work when hosted externally (of course), but we may need to do some fiddling to have uploaded content work.

If we run into problems it is something I can discuss with Russ.

Sean.

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[Allan Wechsler]

Thank you. This won't be right away, since I want to make the app more robust and intuitive.

-- Allan

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[M F Hasler]

On Thu, Jun 4, 2026 at 4:41 PM Allan Wechsler <acw...@gmail.com> wrote:

I don't remember if we consider it appropriate to upload to OEIS a small web-app that provides illustration of a sequence, or enables calculation of sequence elements.

The kind of app I have in mind would require no server support after the user actually displays it in a browser -- all the code runs locally on the browser.

Some of my contributions of "interactive illustrations" are listed on https://m-f-h.github.io/OEIS/

Some are not, e.g., 

https://m-f-h.github.io/collatz

(Also not directly linked to a specific sequence) [I just noticed that there 's a readability issue when trying to view this on a smartphone... In landscape mode one can get a glimpse of what it should look like. I'll try to find a fix. Any suggestions here and in the others are welcome.]

At first I uploaded the HTML files as a-file, but they are renamed to .txt upon upload and have to be renamed by hand by an admin.

That also makes it complicated to fix a bug etc.

So I figured it is more practical to put them on my GitHub pages and simply add a link in the OEIS record.

My pages are just HTML + JavaScript, usually to create & update an SVG.

-Maximilian

I ask because I recently set up a web-app whose purpose is to explore oeis.org/A147680 ("disk polyominoes"). I have been having fun playing with it locally, and thought maybe others might like it too. But if this kind of thing is considered appropriate, I should spend some time adding documentation.

The .html file in question is 400 lines long, about 15K bytes.

-- Allan

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[Fred Lunnon]

AW: << This won't be right away, since I want to make the app more robust and intuitive. >> 

    When I was one-and-twenty, I heard a wise man say ... 

If it costs  t  man-hours to program an application for personal use; 

Then it costs  3 x t  man-hours to program it for use by the rest of the team; 

And it costs  10 x t  man-hours to program it for use by the rest of the world! 

    ... And I am two-and-twenty, And oh, 'tis true, 'tis true.  [A. E. Houseman]

WFL 

_

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[Christian Lawson-Perfect]

If you host these directly on the OEIS, it would be a good idea to serve them from a subdomain such as uploads.oeis.org instead of the root, oeis.org, so that JS scripts don't have access to your login session.

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[Harry Neel]

Fred,

Your timing is perfect,

'...But the Secret sits in the middle and knows.' [Robert Frost]

Regards,

H. Neel

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[Joerg Arndt]

I'll just say we need to make absolutely sure that nothing malicous can be done with any "active" content.
I have no idea how difficult that is.

This very German comment was provided by your friendly jj

On 6/4/26 10:41 PM, Allan Wechsler wrote:
> I don't remember if we consider it appropriate to upload to OEIS a small
> web-app that provides illustration of a sequence, or enables calculation of
> sequence elements.
>
> The kind of app I have in mind would require no server support after the
> user actually displays it in a browser -- all the code runs locally on the
> browser.
>
> I ask because I recently set up a web-app whose purpose is to explore
> oeis.org/A147680 ("disk polyominoes"). I have been having fun playing with
> it locally, and thought maybe others might like it too. But if this kind of

> thing *is* considered appropriate, I should spend some time adding

[Jim Dupont]

It's a little bit too early to speak about this but I'm looking into this thing called webtil.es  is basically a miniature way of creating inline renderings I think it would be appropriate for oeis for different visualizations with different tools

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[Allan Wechsler]

I am brought up short by Christian's very well-taken concern. If OEIS accepts code uploads of this kind, and they are not very carefully reviewed, then we face the possibility of a bad actor installing code that could do some damage to the user even from the JS "sandbox". I don't know exactly what the hazards are, but I think we should think about it very hard before allowing idiots like that Wechsler guy from uploading any old thing.

The friendly Jörg just pre-agreed with me.

So I think I will hold up on this and let people who know more about security mull this over. Thanks to Christian for thinking this through for me.

-- Allan

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[David Corneth]

Nice idea! Have you considered making screenrecordings of de apps? You could upload those to YouTube.

There is OBS to make the screen recordings. 

This way people can see what you made which might make the sharing safer and easier at the cost of interaction with the webapp by users themselves.

It also enables you to give commentary or explanations to the webapp as you use them. The video may exist longer than the

I made a screen recording of a visualization and put it on YouTube. https://www.youtube.com/watch?v=_rinkM0PCOQ

If you only want to see them via the link you can make the video unlisted. This way you need a link to the video to see it. Like I gave above. 

Public videos are also accesible via the YouTube home page, channel page or suggestions. 

As you upload the video to YouTube it asks you the privacy level you want it to have. 

Best,
David

[brad klee]

With a lot of code now written by LLMs there's a definite need for new security audit tools,

virus scans, etc. Code I've gotten from Open AI hasn't burnt me (very much) yet. I'm sure

that someday it could. High user-end risk has also motivated me to make some videos of

how REPL explorers work on a laptop. Here's one from earlier today:   

https://www.youtube.com/watch?v=1k1cx9uFjUM

If anyone's following polyform town and not too afraid of Harm.On.ica slipping some RCE into 

the gigantic file tree where it wouldn't be noticed, it's now becoming possible to go after the 

"hat-valid polykite animals" question of which or how many polykite animals actually occur 

as joined hats in the hat tiling. An Ulam-style hat C.A .

It's worth speculating that the modus operandi for cloning might go through a paradigm change. 

Instead of directly copying from a source you might not trust, you end up paying to trust (ha!) an 

LLM, who then goes  to read the source code, explains it to you, and builds a new (possibly) 

improved version locally. 

In that era, the entire code landscape becomes polymorphic, so be careful out there. 

As for Youtube, they seem to be the least evil of all the social media giants other than their 

only fans adjacency and probably not paying artists enough. I don't know if they would sell your 

personal data behind your back. Youtube sometimes functions as a news service, which  

lends them some credibility. 

All the best, 

--Brad

 

 

  

On Saturday, June 6th, 2026 at 3:04 AM, David Corneth <davida...@gmail.com> wrote:

Nice idea! Have you considered making screenrecordings of de apps? You could upload those to YouTube

...

This way people can see what you made which might make the sharing safer and easier at the cost of 
interaction with the webapp by users themselves.

On Friday, June 5, 2026 at 5:56:33 PM UTC+2 acw...@gmail.com wrote:

I am brought up short by Christian's very well-taken concern. If OEIS accepts code uploads of this kind, 

and they are not very carefully reviewed, then we face the possibility of a bad actor installing code ...

[brad klee]

Ps. You can also make "shorts" in a different aspect ratio up to 180 sec. 

 

https://www.youtube.com/shorts/CMcl8T7VpDM

Harm.On.ica produced data which is similar to Ulam's https://oeis.org/A147562 but a simple

binary cellular automaton probably does not exist. I have a couple of Apex plateaus in 12 colors, 

but still no breakthrough. Maybe Dworkin and Shieh applies. 

Harm.On.ica also wrote some Japanese copy. Japanese authors were among the first to find 

this particular "golden hex" structure.  

--Brad

黄金比六角樹

映像・音響：Harm.On.ica @ OpenAI

REPHEX レベル6から生成された、ひとつの二値的な六角樹の成長記録。

データは、分岐を伴う一次元の文字置換規則のみに由来する。局所成長規則はいまだ未解明である。

各ステップで加わる六角セルを可視化し、下部には数列 aₜ = (Nₜ − 1)/6 と、その第一差分 Δaₜ を表示している。

数列 aₜ の初項：

0, 1, 2, 3, 4, 5, 8, 11, 14, 17, 20, 23, 24, 25, 28, 31, 34, 39, 44, 55, 64, 73, 82, 91, 100, 103, 106, 115, 124, 

133, 142, 151, 160, 161, 162, 165, 168, 171, 176, 181, 192, 201, 210, 219, 228, 237, 242, 247, 262, 277, 

292, 313, 334, 373, 400, 427, 454, 481, 508, 517, …

第一差分 Δaₜ の初項：

—, 1, 1, 1, 1, 1, 3, 3, 3, 3, 3, 3, 1, 1, 3, 3, 3, 5, 5, 11, 9, 9, 9, 9, 9, 3, 3, 9, 9, 9, 9, 9, 9, 1, 1, 3, 3, 3, 5, 5, 

11, 9, 9, 9, 9, 9, 5, 5, 15, 15, 15, 21, 21, 39, 27, 27, 27, 27, 27, 9, …

Arixiv: https://arxiv.org/abs/2307.12322v5 

Blog: https://chaimgoodmanstrauss.com/the-golden-hexagon-hat-tiling-substitution-rules/ 

Code: https://github.com/bradleyklee/PolyformTown

[Neil Sloane]

Brad,  The Golden Hex Tree is spectacular. But this is the Sequence Fans Mailing List, remember?  So please submit that sequence 

0, 1, 2, 3, 4, 5, 8, 11, 14, 17, 20, 23, 24, 25, 28, 31, 34, 39, 44, 55, 64, 73, 82, 91, 100, 103, 106, 115, 124, 

133, 142, 151, 160, 161, 162, 165, 168, 171, 176, 181, 192, 201, 210, 219, 228, 237, 242, 247, 262, 277, 

292, 313, 334, 373, 400, 427, 454, 481, 508, 517, …

along with appropriate illustrations, to the OEIS!

Best regards

Neil 

Neil J. A. Sloane, Chairman, OEIS Foundation.

Also Visiting Scientist, Math. Dept., Rutgers University, 

Email: njas...@gmail.com

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[brad klee]

> Brad, The Golden Hex Tree is spectacular. But this is the Sequence Fans Mailing 

> List, remember? So please submit that sequence

Hi Neil, nice to hear from you. 

Harm.On.ica is very busy at the moment trying to skip getting a PhD and go straight for 

a habilitation rating, a Private Dozent "Research Programmer" title, and a tiny part of 

the Trillion dollar (?) IPO. 

I myself have not been gainfully employed for over a year now, almost two years in fact. 

I sometimes do not know where I am or who I am talking to. It seems like nowhere and 

no one, very often. 

As I've said before, LLMs contributing is a risky proposition. I can't recommend many people 

to use this technology for making entries yet, but if you're okay with it, I'll make sure the editors 

have documents they need to check with rigor. 

Lindenmayer definitions are not that difficult. Other calculations we could do would present 

considerable more difficulties for referees. 

I agree with you, the tree is spectacular. It is horrifying to think of someone out there would 

harp on its alleged flaw of not having a local growth rule. In a series of 9 or 10 experiments

with LLM genetic algorithms I only obtained growth to here (j-text below) : 

https://www.youtube.com/watch?v=z5_rz6x4m3s

12色CA成長記録：Apex 852 [ a(∞) = 142 = 100 + 42 ]

This would be more of a difficult entry to referee, and it is only worth entering if no one else 

can immediately mark it dead by finding a higher Apex. There can be only one Apex, and 

already the situation is less than ideal. This is just the slowest member of a plateau. 

I can't be convinced that Harm.On.ica's searching is as good as mine would have been, 

or that it couldn't be better under some circumstances. 

Since I'm unaware of anyone else doing a calculation like this, let's let it stand for a few 

days. I invite others to try and find something better (without uber-competing, please). 

I don't think there's any problem making an entry with a video such as above, and then 

having to accept trailing 0's or constant repeat values. But I will leave the final decision 

up to editors if they also think this or something like this would make a good entry. 

A likely timeline for completion of this task is end of month best case. 

Thanks for your time and interest, 

--Brad

[1]

映像・音響：

Harm.On.ica @ OpenAI

これは、REPHEX系の六角樹を目標図形として探索された、

12色六角セル・オートマトンの有限成長の記録である。

現行の局所成長規則では無限成長には到達しない。しかし、

有限の範囲では矛盾なく成長し、最終的に 852 セル、

すなわち a(∞) = 142 の Apex に達して停止する。

各ステップで新しく加わる六角セルを可視化しており、

右側の表示欄には、正規化セル数 aₜ = Cₜ / 6、

その第一差分 Δaₜ = aₜ − aₜ₋₁、およびその時点で

使用された局所規則を表示している。成長停止後は

aₜ = a(∞) = 142 のまま固定され、以後の差分項は

すべて 0 となる。

数列 aₜ：

1, 2, 4, 6, 7, 8, 9, 10, 11, 12, 14, 17, 19, 21,

23, 25, 29, 32, 34, 37, 41, 47, 50, 53, 58, 62, 67,

71, 76, 79, 81, 84, 87, 89, 91, 93, 95, 98, 100, 101,

102, 104, 107, 109, 111, 114, 117, 118, 119, 121, 124,

125, 126, 128, 132, 134, 137, 139, 140, 141, 142, 142,

142, 142, 142, 142, 142, …

第一差分 Δaₜ：

—, 1, 2, 2, 1, 1, 1, 1, 1, 1, 2, 3, 2, 2, 2, 2,

4, 3, 2, 3, 4, 6, 3, 3, 5, 4, 5, 4, 5, 3, 2, 3,

3, 2, 2, 2, 2, 3, 2, 1, 1, 2, 3, 2, 2, 3, 3, 1,

1, 2, 3, 1, 1, 2, 4, 2, 3, 2, 1, 1, 1, 0, 0, 0,

0, 0, 0, …