Questions tagged [experimental-mathematics]

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Using Ehrhart polynomials to count primes?

As indicated below, one could use the Ehrhart polynomials of the simplex in number theory. Here are the questions without context first: Questions: The sum $$\sum_{k=0}^t (-1)^k ( \operatorname{...
mathoverflowUser's user avatar
50 votes
1 answer
8k views

What mathematical problems can be attacked using DeepMind's recent mathematical breakthroughs?

I am a research mathematician at a university in the United States. My training is in pure mathematics (geometry). However, for the past couple of months, I have been supervising some computer science ...
Ryan Hendricks's user avatar
2 votes
0 answers
190 views

Zeros of the semiprimes

Let $P$ be the prime zeta function $$ P (s) = \sum_{p\, \in\text{ primes}} \frac 1 {p^s} = \frac {1} {2^s} + \frac {1} {3^s} + \frac 1 {5^s} + \frac 1 {7^s} + \frac 1 {11^s} + \cdots $$ and define the ...
martin's user avatar
  • 1,893
0 votes
0 answers
195 views

Does there exist an $L$-function for any subset of $\mathbb{N}$?

Consider the following prime sum: \begin{aligned} \sum _{p}{\frac {\cos(x\log p)}{p^{1/2}}} \end{aligned} whose spikes appear at the Riemann $\zeta$ zeros as shown here. Taking these detected spikes (...
martin's user avatar
  • 1,893
4 votes
1 answer
285 views

Why should we expect this odd behavior of negative binomial distributions?

In independent Bernoulli trials with probability $p$ of success on each trial, let $X$ be the number of failures before the $n$th success. Then $$ \Pr(X=x) = \binom{-n}{\phantom{+}x} (-q)^x p^n \text{ ...
Michael Hardy's user avatar
-4 votes
1 answer
354 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
3 votes
1 answer
464 views

abc-conjecture and positive definite kernels, again?

One formulation of the abc-conjecture is: $$\forall a,b \in \mathbb{N}: \frac{a+b}{\gcd(a,b)}< \operatorname{rad}\left ( \frac{ab(a+b)}{\gcd(a,b)^3}\right )^2 $$ Let us define: $$K(a,b) := \frac{2(...
mathoverflowUser's user avatar
0 votes
1 answer
116 views

A special kind of pseudo-garden eden states in cellular automata

I'm currently investigating Wolfram's elementary cellular automata on finite grids with periodic boundary conditions, i.e. on $\mathbb{Z}/k$ for different $k$. It is clear that for each rule $R$ and ...
Hans-Peter Stricker's user avatar
2 votes
0 answers
87 views

Primes of the form $a+b^k$ for $k=(a \bmod 2),\ldots,n$?

Procrastinal problem: Given $n$, one can ask for integers $a,b>1$ of different parities such that $a+b^k$ is prime for $k=(a\bmod 2),\ldots,n$. A few examples are: $2+4995825^k$ is prime for $k=0,\...
Roland Bacher's user avatar
2 votes
1 answer
387 views

Mysteries of Wolfram's rule 18

[Unfortunately, I made some mistakes in my original question. I tacitly corrected them wherever I found them.] Wolfram's rule 18 gives rise to fractal patterns, but when started with two black cells ...
Hans-Peter Stricker's user avatar
0 votes
0 answers
98 views

Possible shifts in finite elementary cellular automata

I investigated the long term behaviour of a pair of black cells ■■ on a circle of $N$ cells under the action of each of Wolfram's rules $R$. For each combination $(R,N)$ I determined the first ...
Hans-Peter Stricker's user avatar
2 votes
0 answers
84 views

Curious sequences associated to continuous fractions

Given a strictly positive initial rational number $x_0$ in $\mathbb Q_>$ we define a sequence $x_0,x_1,\ldots$ recursively by setting $x_{n+1}=x_n+1/S(x_n)$ for $S(x)=a_0+a_1+\ldots+a_k$ where $[...
Roland Bacher's user avatar
1 vote
0 answers
367 views

Astonishing affinity of Wolfram's rule 110 to the numbers 2 and 7

I investigated the evolution of a single black cell on 1-dimensional grids with periodic boundary conditions of variable sizes $N$ under Wolfram's rule 110 which is the only one for which Turing ...
Hans-Peter Stricker's user avatar
7 votes
1 answer
183 views

Reporting inconclusive experimental searches

In many areas of mathematics it is informative to conduct numerical experiments. But, it not uncommon that the searches do not lead to the examples or data one was hoping for. Since the numerical ...
Thomas Sauvaget's user avatar
3 votes
0 answers
277 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
6 votes
0 answers
474 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
103 votes
17 answers
15k views

Theorems that are essentially impossible to guess by empirical observation

There are many mathematical statements that, despite being supported by a massive amount of data, are currently unproven. A well-known example is the Goldbach conjecture, which has been shown to hold ...
2 votes
1 answer
235 views

What is wrong with the experimental evidence against the semi strong perfect graph theorem?

We got experimental evidence against the semi strong perfect graph theorem and would like to learn what is wrong with it. From Recognizing the P4-structure of bipartite graph The P4-structure of a ...
joro's user avatar
  • 24.2k
28 votes
1 answer
2k views

Conjectures inspired by AI

Today in Nature a paper described how AI guided mathematicians to make highly non-trivial conjectures, which they managed to prove, one in Knot Theory involving a new invariant, the other in ...
0 votes
1 answer
469 views

New experiments involving Ramanujan primes: Benford's law

I know that in the literature there are interesting articles involving the sequence of Ramanujan primes, I refer the Ramanujan Prime from the online encyclopedia Wolfram MathWorld. This week I ...
user142929's user avatar
7 votes
0 answers
427 views

Dynamics of a curious bijection of $\mathbb N$

The two sequences A48680 and A48679 of the OEIS define two mutually inverse bijections on the set of all strictly positive natural numbers given (for the comfort of the reader) as follows: Given an ...
Roland Bacher's user avatar
72 votes
13 answers
10k views

The use of computers leading to major mathematical advances II

I would like to ask about recent examples, mainly after 2015, where experimentation by computers or other use of computers has led to major mathematical advances. This is a continuation of a question ...
5 votes
2 answers
766 views

Exact formula for partial sums of Liouville function $L(n)$ (OEIS sequence A002819)

I am wondering if it is possible to get a useful exact formula, or at least some useful asymptotics, for the partial sums of the Liouville function (OEIS sequence A002819) $$L(n)=\sum_{k=1}^n \lambda(...
Vincent Granville's user avatar
90 votes
11 answers
13k views

What are possible applications of deep learning to research mathematics?

With no doubt everyone here has heard of deep learning, even if they don't know what it is or what it is good for. I myself am a former mathematician turned data scientist who is quite interested in ...
3 votes
0 answers
303 views

Why the curve $x^2+y^2+y+1=0$ has only one point over $\mathbb{F}_{3^7}$?

According to both sagemath and Magma the curve $x^2+y^2+y+1=0$ has only one point over $\mathbb{F}_{3^7}$. The projective closure has only one point too. Q1 What hypothesis are missing to not violate ...
joro's user avatar
  • 24.2k
41 votes
8 answers
5k views

Examples of creative experiments by mathematicians in modern days

I'm reading Random Circles on a Sphere and the authors did the following to empirically check their results: To make a partial test of the accuracy of the above approximations an experiment was ...
1 vote
1 answer
403 views

When does this limiting ratio give a real root $x$ to the equation of the form $\sum\limits_{k=0}^d \frac{x^k a_{k+1}}{k!}=0$?

By searching the Inverse Symbolic Calculator, we appear to be able to make the following conjecture about a real root to the equation: $$\sum\limits_{k=0}^d \frac{x^k a_{k+1}}{k!}=0 \tag{1}$$ Let the ...
Mats Granvik's user avatar
  • 1,133
45 votes
4 answers
1k views

How to write computer-assisted mathematics well?

Much has been said about writting good papers in mathematics. A short google query yields countless sources of advice. This skill also appears to be quite transferrable between basic branches of ...
3 votes
0 answers
248 views

Some statistics related to the abc conjecture

We did some statistics about the 14 million good abc triples below 10^18 taken from Bart de Smith site. This was examining just the top of the iceberg, since the interesting triples grow very likely ...
joro's user avatar
  • 24.2k
18 votes
8 answers
1k views

Conceptual insights and inspirations from experimental and computational mathematics [duplicate]

I am interested in whether experiments on computers can help identifying new ideas or concepts in Mathematics. I am not talking about confirming particular conjectures up to certain numbers (for ...
5 votes
1 answer
349 views

Gadgets as primality tests

From the literature, showed below, I know two gadgets that provide a way to know if a positive integer (a positive quantity of units) is composite or a prime number. I would like to know if in the ...
user142929's user avatar
0 votes
0 answers
156 views

Similar problems for the Dedekind psi function than those that are in the literature for the Euler's totient function: reference request or proposals

I know the linked articles from Wikipedia for the Euler's totient function and the Dedekind psi function. I know that are in the literature famous, interesting and difficult problems involving the ...
user142929's user avatar
1 vote
0 answers
362 views

The Knuth-Stolarsky conjecture in addition chains

I would like some general feedback on an experiment I have run in the field of addition chains. An addition chain for target integer $n$ is defined as: $$1=a_0<a_1<\cdots<a_r=n \text{ with } ...
Neill Clift's user avatar
5 votes
1 answer
600 views

Modified Pascal's triangle

I posted this question to Mathematics Stack Exchange but got no answers. I hope that this question is advanced enough for this forum: In Pascal's triangle, each number is the sum of the two numbers ...
We Pretty's user avatar
3 votes
0 answers
293 views

Growth functions of finite group - computation, typical behaviour, surveys?

Looking on the growth function for Rubik's group and symmetric group, one sees rather different behaviour: Rubik's growth in LOG scale (see MO322877): S_n n=9 growth and nice fit by normal ...
Alexander Chervov's user avatar
3 votes
1 answer
204 views

$\psi(2,1/6),\psi(4,1/6)$ in terms of zeta and pi only and another closed form for zeta

Let $\psi(n,x)$ denote the polygamma function. In this answer Lucia gave linear relations for $\psi(m,1/3),\psi(m,1/6),\zeta(m+1)$. The computer managed to find closed form for $\psi(2,1/6)$ and $\...
joro's user avatar
  • 24.2k
6 votes
1 answer
385 views

$\pi$ in terms of polygamma

The computer found this, but couldn't prove it. Let $\psi(n,x)$ denote the polygamma function. With precision 500 decimal digits we have: $$ \pi^2 = \frac{1}{4}(15 \psi(1, \frac13) - 3 \psi(1, \...
joro's user avatar
  • 24.2k
1 vote
1 answer
243 views

Understanding a group of transformations of the plane $\mathbb{Z} \times \mathbb{Z}$

I'm doing some research in visualizing arithmetic sets (resp. properties, resp. sequences of integers). I try to create patterns (in which I hope to observe some symmetries) by injectively mapping $\...
Hans-Peter Stricker's user avatar
5 votes
1 answer
1k views

Periods in the trivial extension algebra of the incidence algebra of the divisor lattice

Definition of $C_L$ for people who like number theory: Let $m$ be a number with prime factorisation $m=p_1^{n_1} ... p_r^{n_r}$ with $n_i>0$. Define $I_m$ to be the incidence algebra of the ...
Mare's user avatar
  • 25.7k
17 votes
3 answers
703 views

Automated search for bijective proofs

In enumerative combinatorics, a bijective proof that $|A_n| = |B_n|$ (where $A_n$ and $B_n$ are finite sets of combinatorial objects of size $n$) is a proof that constructs an explicit bijection ...
Timothy Chow's user avatar
2 votes
0 answers
117 views

Conjectures that can be tested with large numbers of Hecke eigenvalues of GSp(4) automorphic forms

As part of my thesis work I have proved Ibukiyama's conjecture implies something about $\mathrm{SO}(5)$ forms associated to certain lattices lifting to $\mathrm{GSp}(4)$ (This was originally a ...
2 votes
2 answers
628 views

Expansion of inverse logarithmic integral in terms of lambert w

Cipolla and Césaro both gave expansions of $\operatorname{li}^{-1}$ in tems of nested $\log$ functions. I think it can be written in terms of the Lambert-W function in the form: $\operatorname{li}^{-...
martin's user avatar
  • 1,893
77 votes
13 answers
8k views

What computational problems would be good proof-of-work problems for cryptocurrency mining?

What computational mathematics problems that could be used as proof-of-work problems for cryptocurrencies? To make this question easier to answer, I want proof-of-work systems that work in ...
Joseph Van Name's user avatar
32 votes
1 answer
913 views

Strange convergence of Euler's series for $\zeta(2)$

Using Maple to compare $\pi^2$ and the partial sums of $6\sum_{n=0}^{\infty}\frac{1}{n^2}$ I have noticed something that appears strange. For instance, let $S_{k}=6\sum_{n=0}^{k}\frac{1}{n^2}$ be ...
Pedro Namtior's user avatar
18 votes
1 answer
697 views

Several conjectured identities for polylogarithms

I asked a question at M.SE a couple of years ago about polylogarithms $\!^{[1]}$$\!^{[2]}$$\!^{[3]}$$\!^{[4]}$ where I conjectured $$720\,\operatorname{Li}_4\!\left(\tfrac12\right)-2160\,\operatorname{...
Vladimir Reshetnikov's user avatar
9 votes
3 answers
1k views

May $p^3$ divide $(a+b)^p-a^p-b^p$?

Do there exist positive integers $a,b$ and a prime $p>\max(a,b)$ such that $p^3$ divides $(a+b)^p-a^p-b^p$? The reader of Kvant magazine A. T. Kurgansky asked to prove that such $a,b,p$ do not ...
Fedor Petrov's user avatar
114 votes
3 answers
5k views

The number $\pi$ and summation by $SL(2,\mathbb Z)$

Let $f(a,b,c,d)=\sqrt{a^2+b^2}+\sqrt{c^2+d^2}-\sqrt{(a+c)^2+(b+d)^2}$. (it is the defect in the triangle inequality) Then, we discovered by heuristic arguments and then verified by computer that $$\...
Nikita Kalinin's user avatar
2 votes
0 answers
228 views

On the cardinality of the set of right-truncatable primes

We say that the (base ten) prime number $p=a_{n}a_{n-1}a_{n-2}\cdots a_{1}a_{0}$ is right-truncatable if all of the following numbers are prime: \begin{eqnarray*}a_{n},\\a_{n}a_{n-1},\\ a_{n}a_{n-1}...
José Hdz. Stgo.'s user avatar
9 votes
2 answers
624 views

Periodicity in iterated powers of sin, cos, exp

Given a complex number $z$, consider the sequence \begin{align*} a_0 & = 1\\ a_1 & = (cos(1))^z\\ a_n & = (cos(a_{n-1}))^z \end{align*} This question is about trying to understand ...
Niles's user avatar
  • 589
17 votes
6 answers
2k views

Which journals publish experimental results in pure maths?

All pure mathematicians know that the goal is to produce insight, rather than to simply obtain results. However, it might sometimes be of value to disseminate largely empirical work. In the same ...