I started recording them on 3” × 5” file cards

January 11, 2023 10:10 AM

Mathematician and numeric encylopedstrian N. J. A. Sloane looks back on the history of his work and collaborations on what became the wonder that is the OEIS in a brief and very accessible paper, “A Handbook of Integer Sequences” Fifty Years Later.

And to put a face to a name (or to have an "a ha!" reminder moment, if you're the sort who watches math youtube), here's Sloane in one of many math explainer videos he's done over the years: Terrific Toothpicks on Numberphile.

posted by cortex (10 comments total)

They're all good sequences, Bront.
posted by genpfault at 10:31 AM on January 11, 2023 [5 favorites]

The PDF renders mostly ok as HTML (except for Figures 8 and 9) on arxiv-vanity
posted by vacapinta at 10:42 AM on January 11, 2023

I think I've found myself. "Plain Bob Minimus": 2, 1, 4, 2, 3, 4, 1, 3, 3, 1, 2, 3, 4, 2, 1, 4, . . .
posted by BobTheScientist at 12:45 PM on January 11, 2023

His 1984 article The Packing of Spheres is one of the best math articles Scientific American ever published.

The proof of the Kepler conjecture about the densest possible packing in 3 dimensions, which was the subject of only a part of Sloane's article, wasn’t achieved until 1998, and was so difficult and complex that it couldn’t be fully confirmed until 2014.
posted by jamjam at 12:49 PM on January 11, 2023 [1 favorite]

I'm proud to be included with this simple sequence even if it's not very ... mathematical.
posted by dmd at 2:42 PM on January 11, 2023 [5 favorites]

I was introduced to Sloane's integer sequences in high school, in website form. In grad school, we found an actual copy of the book kicking around at UQÀM, and I don't think it had occurred to any of us that there had been a book. It's somehow telling, though, that I nonetheless call it "Sloane's integer sequences" and not OEIS.
posted by hoyland at 4:32 PM on January 11, 2023

In David Wells's The Penguin Dictionary of Curious and Interesting Numbers, it is stated that 39 "appears to be the first uninteresting number, which of course makes it an especially interesting number, because it is the smallest number to have the property of being uninteresting."

This is a little unfair to the number 39, which (as of two years ago) was an index term for 28,633 sequences in OEIS -- though maybe Wells was onto something, since this hit count was lower than for any other integer until 46.

Why do I have this data? In 2021, I was teaching statistics, and I had my students explore the "interestingness" function which assigns each integer its number of occurrences in OEIS. While smaller numbers unsurprisingly appear more often than larger ones, it turns out there are very distinct clusters of interesting and uninteresting numbers. I also had my class extrapolate from the first 2000 hit counts, keeping in mind the variability, to estimate the first number with no OEIS hits. On the day I assigned them the project, that number was 17,843. But by the time I graded it, someone had posted the continued fraction convergents for an equal-tempered semitone pitch ratio. Lucky for the student who guessed "around 20,000"; the new smallest uninteresting number was, and still is, 20,067.
posted by aws17576 at 5:57 PM on January 11, 2023 [5 favorites]

Ha! I first learned about Sloan's integer sequences about a month ago when a bunch of people on Twitter were discussing this question: "What is the largest number, such that you cannot order exactly that many chicken nuggets from McDonalds". Eventually someone suggested adding this to Sloan, and it transpired that McNugget Numbers was already on there!
posted by itsatextfile at 8:07 PM on January 11, 2023 [1 favorite]

The “strobogrammatic sequence,” of numbers whose value is unchanged if you rotate the number by 180°, mistakenly contains “99” instead of “88” on the fifth page. It doesn’t help that the text invites the reader to “guess!” what rule generates this sequence. A hint to the typo is that …,11,69,99,96,111,… is not strictly increasing, but of course there isn’t any rule that a sequence of integers can only be strictly increasing.

It’s correct in the linked A000787, where there is code to generate it.

Which mostly goes to point out that keeping the error rate low in a project like this one is really hard.
posted by fantabulous timewaster at 5:51 AM on January 12, 2023 [2 favorites]

Sadly they replaced the 9-piece McNugget with the 10-piece (in the US, I'm not going to speak for other markets), so it's impossible to buy an odd number of McNuggets anymore. You can get 4, 6, 10, 20, or 40. And as a result you can make every even number of McNuggets except 2, which isn't interesting.

(Historically the "McNugget problem" allowed packages of 6, 9, or 20 McNuggets, omitting the kid-size 4... from 6, 10, or 20 the only even numbers you can't make are 2, 4, 8, or 14.)
posted by madcaptenor at 7:45 AM on January 12, 2023 [1 favorite]