Jan Marthedal RasmussenDec 18

Prime Factors of Factorial Numbers https://janmr.com/posts/prime-factors-of-factorial-numbers/ #math #prime #factors #factorials

\[
d_p(n!) = \sum_{k=1}^\infty \left\lfloor \frac{n}{p^k} \right\rfloor = \sum_{k=1}^{\lfloor \log_p(n) \rfloor} \left\lfloor \frac{n}{p^k} \right\rfloor
\]

janmr.com | Prime Factors of Factorial Numbers

N-gated Hacker NewsJul 21, 2025
Ah yes, the ancient art of hiding your diary entries in a deck of cards, because #encryption is just too mainstream 🤡🔢. A blog post that is essentially a math lesson disguised as a magic trick, but without any of the actual magic. Apparently, #factorials are the new secret code—move over, spies! 🕵️‍♂️🃏
https://asherfalcon.com/blog/posts/3 #diaryhacks #mathmagic #secretcodes #HackerNews #ngated
Asher Falcon

Asher Falcon's personal website - Software engineer and student

Hacker NewsJun 23, 2025

Finding a billion factorials in 60 ms with SIMD

https://codeforces.com/blog/entry/143279

#HackerNews #Finding #a #billion #factorials #in #60 #ms #with #SIMD #codeforces #SIMD #performance #factorials #computing

Hacker NewsMar 28, 2025

Decomposing a Factorial into Large Factors

https://terrytao.wordpress.com/2025/03/26/decomposing-a-factorial-into-large-factors/

#HackerNews #Decomposing #a #Factorial #into #Large #Factors #mathematics #factorials #algorithms #numbertheory #TerryTao

Decomposing a factorial into large factors

I’ve just uploaded to the arXiv the paper “Decomposing a factorial into large factors”. This paper studies the quantity $latex {t(N)}&fg=000000$, defined as the largest quanti…

What's new
MazzoJun 6, 2024
 made colored #factorials in 2 lines  
#python
Show threadBobulous  Apr 8, 2024

@atamakahere Surely that would need to limit itself to u8 as the input and u128 as the output? And even then you'd need a hard limit enforced on the input value because 255! is equal to more than 3.35E104, whereas u128::MAX is less than 3.5E38.

In fact, the biggest number which fits is 34! equal to roughly 2.95E38.

Factorials grow up so fast.

#RustLang #factorials

Justin at Ecoscore AustraliaFeb 1, 2023

#factorials #math
From @waitbutwhy
February has 28 days (7 x 4). Each day has 24 hours (8 x 3). Each hour has 60 minutes (6 x 5 x 2).

So February has 8! minutes:
8 x 7 x 6 x 5 x 4 x 3 x 2 x 1.

Show threadBigDiceDaveOct 12, 2018

I sent that 1000! picture to a friend on #Hangouts (which #Google hasn't shut down... yet), and my friend commented on the large number of 0s at the end of the value.

I assured him that that's what happens with #factorials - by 5! you've got 2*5 as a subexpression, and by 10! you've got another factor of 10, well, right there. 15 brings in another factor of 5, and by that point, you've got a backlog of 2s. 25! has six trailing zeroes, with two factors of 5 right there.

That's #math for you.