# Lost anecdote of a mathematician who gave a presentation without saying a word [closed]

Some weeks ago I saw in a blog post an anecdote of a mathematician who once gave a 'talk' (not really). The special thing was that he came directly to the chalkboard and started doing one computation that took several empty boards. Without saying a word during all the process (in fact all the presentation), when he put the last dot in the computation, the crowd started clapping excitedly.

I sort of remember and I wanted to come back to it to read it with more time, but I lost it. Now I have the doubt. Does anyone know about this anecdote? Who can this mysterious mathematician be?

Thanks!

• If you just google your title, "mathematician who gave a presentation without saying a word", the first result is hsm.stackexchange.com/q/2105/3301, which has the answer... – AccidentalFourierTransform May 8 '18 at 14:28
• This question is not about mathematics, within the scope defined in the help center. Instead, it is about the history of mathematics, and has an answer on HSMSE. – Xander Henderson May 8 '18 at 15:54
• @XanderHenderson: The help center lists history of mathematics under the category "There are certain subjects that, while still on-topic here, might be better addressed by one of our sister sites:" Linking to HSM is appropriate; closing as off-topic is not. – Micah May 8 '18 at 19:00
• I'm voting to close this question as off-topic because it has already been asked and answered at the historyOfMath.SE site: hsm.stackexchange.com/q/2105/3301 – amWhy May 8 '18 at 19:26
• @XanderHenderson: I agree that the other answer (which I upvoted) is superior to the answer here (which I wrote in about five minutes right before going to bed). My disagreement is with your claim that being about the history of mathematics means that it is off-topic on MSE (e.g., see this meta post). If you want to claim that being a duplicate of a question on another site is close-worthy, I won't argue too much, but that doesn't make it off topic. – Micah May 8 '18 at 19:39

Probably it was about Frank Nelson Cole's factorization of $2^{67}-1$. As Wikipedia says:
On October 31, 1903, Cole famously made a presentation to a meeting of the American Mathematical Society where he identified the factors of the Mersenne number $2^{67} − 1$, or $M_{67}$. Édouard Lucas had demonstrated in 1876 that $M_{67}$ must have factors (i.e., is not prime), but he was unable to determine what those factors were. During Cole's so-called "lecture", he approached the chalkboard and in complete silence proceeded to calculate the value of $M_{67}$, with the result being $147,573,952,589,676,412,927$. Cole then moved to the other side of the board and wrote $193,707,721 \times 761,838,257,287$, and worked through the tedious calculations by hand. Upon completing the multiplication and demonstrating that the result equaled $M_{67}$, Cole returned to his seat, not having uttered a word during the hour-long presentation. His audience greeted the presentation with a standing ovation. Cole later admitted that finding the factors had taken "three years of Sundays."
• @Peter: How long would you estimate it takes you to compute $2^{67}-1$, though? – Asaf Karagila May 8 '18 at 9:10
• @AsafKaragila: I can write down $2^{20}=1048576$ and $2^7=128$ from memory; then three long multiplications and subtract one. – hmakholm left over Monica May 8 '18 at 9:31
• Didn't someone at around the same time, or maybe in the late 19th century, spend several months manually factoring $2^{4n + 2} + 1$ for some numerical value of n around 20, after which someone pointed out to him that this equals $4 . 2^{4n} + 4 . 2^n + 1 - 4 . 2^n$, which is a difference of two squares? ;-) – John R Ramsden May 9 '18 at 14:15