# Community Promotion Ads - 2018 [duplicate]

It's almost February in 2018, which isn't supposed to be the proper time to cycle these, but for this year it'll be once again, so we'll be refreshing the Community Promotion Ads for this year now!

### What are Community Promotion Ads?

Community Promotion Ads are community-vetted advertisements that will show up on the main site, in the right sidebar. The purpose of this question is the vetting process. Images of the advertisements are provided, and community voting will enable the advertisements to be shown.

### Why do we have Community Promotion Ads?

This is a method for the community to control what gets promoted to visitors on the site. For example, you might promote the following things:

• useful tools or resources for the mathematically inclined
• interesting articles or findings for the curious
• cool events or conferences
• anything else your community would genuinely be interested in

The goal is for future visitors to find out about the stuff your community deems important. This also serves as a way to promote information and resources that are relevant to your own community's interests, both for those already in the community and those yet to join.

### Why do we reset the ads every year?

Some services will maintain usefulness over the years, while other things will wane to allow for new faces to show up. Resetting the ads every year helps accommodate this, and allows old ads that have served their purpose to be cycled out for fresher ads for newer things. This helps keep the material in the ads relevant to not just the subject matter of the community, but to the current status of the community. We reset the ads once a year, every December.

The community promotion ads have no restrictions against reposting an ad from a previous cycle. If a particular service or ad is very valuable to the community and will continue to be so, it is a good idea to repost it. It may be helpful to give it a new face in the process, so as to prevent the imagery of the ad from getting stale after a year of exposure.

### How does it work?

The answers you post to this question must conform to the following rules, or they will be ignored.

1. All answers should be in the exact form of:

[![Tagline to show on mouseover][1]][2]

[1]: http://image-url
[2]: http://clickthrough-url


Please do not add anything else to the body of the post. If you want to discuss something, do it in the comments.

2. The question must always be tagged with the magic tag. In addition to enabling the functionality of the advertisements, this tag also pre-fills the answer form with the above required form.

### Image requirements

• The image that you create must be 300 x 250 pixels, or double that if high DPI.
• Must be hosted through our standard image uploader (imgur)
• Must be GIF or PNG
• No animated GIFs
• Absolute limit on file size of 150 KB
• If the background of the image is white or partially white, there must be a 1px border (2px if high DPI) surrounding it.

### Score Threshold

There is a minimum score threshold an answer must meet (currently 6) before it will be shown on the main site.

You can check out the ads that have met the threshold with basic click stats here.

## marked as duplicate by JNat♦Feb 7 at 13:25

• Shouldn't there be a recommendation to provide a text version of the ad in the comments, for searchability? – Samuel Lelièvre Aug 1 '18 at 11:31
• Someone should change all the links in here to https:// – RaisingAgent Sep 3 '18 at 12:07

• repost from last year – Grigory M Feb 1 '18 at 21:29
• To quote Brian M. Scott: «This one’s so useful that I even donate a little to them each year» (me too). – Grigory M Feb 1 '18 at 21:30
• I've always been a little puzzled by this one's popularity... how often does one need to look up some sequence of integers? Is it actually of practical use or is it mainly for sequence enthusiasts? – rschwieb Feb 8 '18 at 15:36
• @rschwieb In my case, not terribly often (but then again I don't work very much), but it can be incredibly useful. Just as an example, here is a problem that got a "solution" thanks to OEIS. More generally, I think OEIS makes a nice bridge: lots of discrete things lead to integer sequences. You might work on something, get some numbers, head to OEIS, and find your work is equivalent to some other neat things (which may or may not have been more fully studied). – pjs36 Feb 8 '18 at 17:08
• «Pursuing these identities (…) I found that there exists a formula of the same degree of elegance (…) whenever $d$ belongs to the following sequence of integers: $$d=3, 8, 10,14,15, 21, 24, 26, 28, 35, 36,...$$ I stared for a little while at this queer list of numbers (…) they made no sense to me. (…) So I missed the opportunity of discovering a deeper connection between modular forms and Lie algebras.» // Freeman J. Dyson, Missed opportunities, Bull. AMS 78 (1972) – Grigory M Feb 8 '18 at 21:53
• @rschwieb Integer sequences are everywhere — from simple combinatorial and number theory problems to coefficients of various power series to dimensions of various objects (irreducible representations of algebras, homotopy groups of spaces, various homology groups…). OEIS helps one to guess answers (and it's usually much easier to solve a problem once you know the answer) and (sometimes) to discover some unexpected connections. Yes, in some situations it's very useful. – Grigory M Feb 8 '18 at 22:09
• @GrigoryM Before commenting, I thought it was much as you described, it’s just that I couldn’t believe it would happen frequently enough to count as “incredibly useful”. Maybe once a year at most? In the whole time I’ve thought about research, only one sequence presented itself to me. I guess all it takes is one beautiful connection, though, for the tool to prove itself. – rschwieb Feb 8 '18 at 23:04
• @rschwieb Well, yes, it obviously depends on what kind of mathematics you're doing (and in what style). I like enumerative & algebraic combinatorics — where OEIS is quite helpful (and from time to time I see questions on Math.SE where OEIS could have been of help to OP…) – Grigory M Feb 10 '18 at 14:39

• Reposting last year's version. – André 3000 Jan 30 '18 at 1:41
• Does anyone know if there’s a CoCalc ad anywhere? Searches haven’t turned anything up. I ask because the success of CoCalc (formerly SageMathCloud, if I understand correctly) is very important to William Stein – pjs36 Jan 30 '18 at 22:38
• There is one now! – Samuel Lelièvre Aug 1 '18 at 11:27

• Repost from last year. – Wei Zhong Jan 30 '18 at 17:17

• Reposted from yesteryear. – Lucian Feb 8 '18 at 2:21

• Oh my gosh yes, I don't think this tool gets enough credit. It's simple yet surprisingly powerful. – NetherGranite Mar 23 '18 at 19:22

• It is difficult to read "you need" over the dark red on the right side, especially when the image is smaller – Karl May 10 '18 at 18:30
• @Karl: Then don't read it. The sentence makes sense either way. :-) – Lucian May 11 '18 at 0:41

• This is a demonstration post to indicate how this should look when an ad is posted. It also doubles as your twitter ad, but it's up to you if you wish to promote it by voting – Grace Note Jan 29 '18 at 5:13

• Shouldn't there be some description in the picture? I had to hover my mouse over it and decipher the url to see that what it was. I have given a course on Maxima, but I didn't recognize the logo... – Joonas Ilmavirta Feb 11 '18 at 14:33

• This is a work with my friend. Apparently we are not big companies like the above. – Zaid Alyafeai Feb 4 '18 at 13:01

• There are size requirements for the images, and I do not think this meets them, unfortunately. – pjs36 Feb 2 '18 at 23:17
• @pjs36 I don't know a way to fix it. Should I delete my answer? – polfosol Feb 3 '18 at 8:31
• @pjs36: Size problem fixed ! – Lucian Feb 8 '18 at 1:40
• @polfosol: It's fixed now, so, if size requirements were its only problem, this answer should garner a positive score by the first of March. – Lucian Feb 8 '18 at 2:10