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1 answer
605 views

Multiplicative Persistence - Highest persistence found? [closed]

tried to ask on the math reddit but got deleted due to my account being new. Is the record for highest multiplicative persistence found still 11? As I may have just found a number with persistence of ...
mwt2212's user avatar
  • 21
6 votes
0 answers
479 views

Existence of an explosive prime

The motivation to introduce explosive prime is Carmichael's totient conjecture (see why below). Let $\mathbb{N}_{SF}$ be the set of positive square-free integers. Consider the map $f:\mathbb{N}_{SF} \...
Sebastien Palcoux's user avatar
3 votes
0 answers
283 views

Math videos featuring interesting data animations

I am looking for interesting videos featuring pure data animations (not someone talking about math, but a video featuring some math phenomenon). I am interested in videos that tell a story, rather ...
Vincent Granville's user avatar
20 votes
4 answers
2k views

Does the set of happy numbers have a limiting density?

A positive integer $n$ is said to be happy if the sequence $$n, s(n), s(s(n)), s(s(s(n))), \ldots$$ eventually reaches 1, where $s(n)$ denotes the sum of the squared digits of $n$. For example, 7 is ...
Dave R's user avatar
  • 856