Whatever your grievances against 2016 as a year, it was a stellar number. Like a picnic with milkshakes and beer, this integer was fun for the whole family.

Just look at these equations:

After this crowd-pleaser came 2017, a prime year, which engendered this brilliant Tweet from Matt Parker:

That brings us to 2018.

It’s not triangular, like 2016.

It’s not prime, like 2017.

Is it, then, worthless?

Well, I myself am neither triangular nor prime. But if the roles were reversed, I like to think 2018 would do its best to uncover my special qualities and catalogue them in a blog post. So I went to do “research” (my codeword for “Google searches”).

What secret mathematical properties and pleasures will our new year contain?

To 2018’s credit, there are a few special days to mark on your calendars:

That’s just around the corner! And there’s another one coming:

And then in February, the first of our factor days:

The second will follow in March:

And the third in June:

With another special day in August:

And the final factor day in September:

Exciting as these days are, they pale in urgency alongside the fact that 2018 is the year in which the film Iron Sky takes place. So if there’s a shadow civilization of Nazis living on the dark side of the moon, expect them to surface sometime in the next 12 months.

In another dark turn, 2018 marks the 500^{th} anniversary of the great Dancing Plague, in which four hundred citizens of Strasbourg danced for days without rest, some to their deaths. The cause remains unknown.

(Seriously. I’m not making that one up.)

Aside from that… I’m afraid 2018 is a rather bland number. Well, not bland; let’s go with “understated.” I can’t call it outright “boring” because of the classic proof that there is no uninteresting positive integer:

Still, I have to confess that 2018 is below-average for mathematical swagger. The best I can offer is this little trifecta:

Or, if you prefer strange conversions to and from binary:

I’m afraid I’m not serving well as 2018’s advocate, since this is all rather arbitrary and numerological. We’d get similar answers from an astrologer or a fever dream.

The harsh mathematical truth of 2018 is that it is “semiprime,” i.e., a product of two primes—in this case, 2 x 1009.

That’s not the most exciting property. Other semiprime numbers include 6, 9, 10, 14, 15, 21, 22, 25, 26… and indeed, more than a quarter of all years that have happened so far.

Is that the best we can say for the forthcoming year?

Luckily, no. 2018 has one last trick up its sleeves.

Although semiprime years are quite common, this is the first since 2005. That 13-year drought is rather impressive; it’s the longest since Shakespeare’s death.

With any luck, that’s interesting enough to last us until the Moon Nazis show up.

so very exciting to see that my birthday shall be celebrated worldwide this year on Palindrome Day!

January 18, 1/18/18 is also a Factor Day.

Good point! Need a long row of cupcakes for that one

Don’t forget e day 2/7/18

!!!

Can’t believe I missed this. Crucial. Maybe deserving of its own post in February (which the international folks can read in July if they prefer).

Of course your international audience has a completely different set of dates. As the Month/ Day/Year format is uniquely American.

and by the incredibly warped thinking of the majority of Americans…the whole world is wrong in their formatting of dates. lol

The historical context is that we adopted this convention to separate ourselves from our “colonial oppressors.” It is something we do just to be different! So, it is a little strange to impose cultural hegemony at this time.

If we were are going to be “rational” about it, YMD (HMS) is the way to go. It sorts better and has the date and time together proceeding from most general to most specific.

Absolutely agree — in fact, that’s how I tend to write dates. That way, no one’s happy except my computer.

An international standard for writing dates happens to exist: ISO 8601.

Ack, I should have foreseen that my choice of the American format would stoke the flames of the ongoing date wars!

I agree YYYY-MM-DD is the best format; I have no particular preference between the American and international conventions, except insofar as I grew up on the American one and spent three years in England perpetually confused about dates.

The November survey suggested that this blog’s readership is about 55% American, so I suspect there’s a slight and silent majority that shares my preference.

Yup. Was about to say this too!

Yeah, dude! I thought you were in London.

Was in Birmingham; back in the US of A now!

My condolences… We escaped to New Zealand. Never looking back.

To be fair, I hear New Zealand touted as the ideal escape when the mid-21st century apocalypse hits, whereas I haven’t heard the same case made for the West Midlands.

Alternative for the middle top ‘toon:

We have one spine, one butt, two cheeks…

I believe that 11 is 3, not 2.

However, the sum of all of the decimal digits in 2018 is 11, which is equal to the binary reading of the sum of the prime factors of the oncoming year.

This… is a good point.

2019 = 3 x 673 appears to be another semi-prime year, so we’re going to have two of these in a row.

cue up the Third Eye Blind!

Fabulous – I am most excited about the Fibonacci day

Hello!

A professor in Italy find out that 2018 = 13^2 + 43^2, that is 2018 is a Pitagorean number. Please, note that 13 and 43 are prime numbers.

Happy Golden Ratio Day!