You're reading: Posts By Christian Lawson-Perfect

The OEIS now contains 300,000 integer sequences

The Online Encyclopedia of Integer Sequences just keeps on growing: at the end of last month it added its 300,000th entry.

Especially round entry numbers are set aside for particularly nice sequences to mark the passing of major milestones in the encyclopedia’s size; this time, we have four nice sequences starting at A300000. These were sequences that were originally submitted with indexes in the high 200,000s but were bumped up to get the attention associated with passing this milestone.

Proof by sedition

\[ n > 2 \]

An unexpected bit of controversy involving mathematical notation hit the internet last week, when China's government briefly blocked all Chinese internet users from viewing any page or message containing the letter n.

Apparently, those in charge of the Great Firewall feared that those who disapproved of Xi Jinping removing the two-term limit on his presidency of China would use the letter n to refer to the now-arbitrary number of terms for which he can remain in power.

There's some more context in a post by Victor Mair on Language Log, and in the Guardian.

Faces of Women in Mathematics

This is nice for International Women's Day. Filmmaker Irina Linke and mathematician Eugénie Hunsicker have put together this montage of women in maths from all around the world.


Stanisław Ulam biopic

There's going to be a biopic of physicist/mathematician Stanisław Ulam, titled Adventures of a Mathematician.

Hollywood seems to be working its way through 20th century mathematicians – off the top of my head, there have recently been biopics of John Nash, Alan Turing, Stephen Hawking and Srinivasa Ramanujan. What I want to know is, when do we get Michael Sheen playing John Horton Conway?

There's some information about Adventures of a Mathematician, starring Jakub Gierszal as Ulam, at ScreenDaily.

via MathFeed on Twitter.

Are you more likely to be killed by a meteor or to win the lottery?

This tweet from the QI Elves popped up on my Twitter timeline:

In the account’s usual citationless factoid style, the Elves state that you’re more likely to be crushed by a meteor than to win the jackpot on the lottery.

The replies to this tweet were mainly along the lines of this one from my internet acquaintance Chris Mingay:

Yeah, why don’t we hear about people being squished by interplanetary rocks all the time? I’d tune in to that!

$2^{77,232,917}-1$ is the new $2^{74,207,281}-1$

We now know 50 Mersenne primes! The latest indivisible mammoth, $2^{77,232,917}-1$, was discovered by Great Internet Mersenne Prime Search user Jonathan Pace on the 26th of December 2017. As well as being the biggest Mersenne prime ever known, it’s also the biggest prime of any sort discovered to date.

GIMPS works by distributing the job of checking candidate numbers for primality to computers running the software around the world. It took over six days of computing to prove that this number is prime, which has since been verified on four other systems.

Pace, a 51-year old Electrical Engineer from Tennessee, has been running the GIMPS software to look for primes for over 14 years, and has been rewarded with a \$3,000 prize. When a prime with over 100 million digits is found, the discoverer will earn a \$50,000 prize. That probably won’t be for quite a while: this new prime has $23{,}249{,}425$ decimal digits, just under a million more than the previous biggest prime, discovered in 2016.

If you’re really interested, the entire decimal representation of the number can be found in a 10MB ZIP file hosted at mersenne.org. Spoiler: it begins with a 4.

More information: press release at mersenne.org, home of the Great Internet Mersenne Prime Search.

via Haggis the Sheep on Twitter

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