User joro

113 votes

25 answers

37k views

Examples of math hoaxes/interesting jokes published on April Fool's day?

asked Apr 1, 2016 at 7:12

78 votes

49 answers

45k views

Examples of interesting false proofs

asked Apr 21, 2012 at 14:26

44 votes

1 answer

17k views

Conjecturally unsafe RSA primes $p=27a^2+27a+7$

asked Oct 18, 2017 at 13:02

43 votes

3 answers

19k views

Which integers can be expressed as a sum of three cubes in infinitely many ways?

asked Aug 8, 2013 at 7:06

37 votes

12 answers

3k views

Interesting conjectures "discovered" by computers and proved by humans?

asked Mar 25, 2012 at 9:26

33 votes

4 answers

4k views

Can the difference of two distinct Fibonacci numbers be a square infinitely often?

asked Jan 3, 2012 at 10:54

26 votes

1 answer

2k views

Possible counterexample to a theorem assuming Lang's conjecture

asked Apr 27, 2014 at 10:14

21 votes

4 answers

1k views

Are there open problems for primes which are known for probable primes?

asked Sep 1, 2015 at 8:14

19 votes

1 answer

1k views

Is OEIS A007018 really a subsequence of squarefree numbers?

asked Jan 4, 2013 at 12:27

19 votes

4 answers

3k views

zeta(3) in terms of derivatives of zeta at 1/2 and pi

asked May 5, 2013 at 9:53

18 votes

1 answer

2k views

Conjecture: The number of points modulo $p$ of certain elliptic curve is $p$ or $p+2$ for $p$ of form $p=27a^2+27a+7$

asked Oct 18, 2017 at 10:54

16 votes

1 answer

696 views

A counterexample to a conjecture of Nash-Williams about hamiltonicity of digraphs?

asked Mar 11, 2013 at 10:37

15 votes

1 answer

2k views

Forbidden polynomial identities by the abc conjecture

asked Nov 17, 2012 at 9:33

15 votes

1 answer

1k views

Is deciding if one planar graph is dual to another really NP-hard (Wikipedia claim)?

asked Feb 9, 2016 at 9:27

14 votes

5 answers

1k views

Bounds for constructing $n!$ with additions, subtractions, and multiplications starting from $1$

asked Jan 24, 2015 at 11:51

14 votes

2 answers

4k views

Consequences of technically proving anything in Coq (on at least Linux) exploiting a bug? [closed]

asked May 3, 2011 at 15:07

14 votes

5 answers

976 views

Is the sequence $a_n=c a_{n-1} - a_{n-2}$ always composite for $n > 5$?

asked Oct 28, 2013 at 13:36

13 votes

0 answers

718 views

Is "OEIS A001935 Number of partitions with no even part repeated" efficiently computable $\mod 4$?

asked Mar 22, 2011 at 15:35

13 votes

1 answer

760 views

Infinitely many integer solutions to $X^4+Y^4-18Z^4= -16$

asked Apr 8, 2018 at 8:23

12 votes

3 answers

896 views

What CASes say about the analytic rank of rank 8 elliptic curve '457532830151317a1'

asked Nov 12, 2012 at 8:03

11 votes

1 answer

864 views

Up to $10^6$: $\sigma(8n+1) \mod 4 = OEIS A001935(n) \mod 4$ (Number of partitions with no even part repeated )

asked Mar 22, 2011 at 12:13

11 votes

1 answer

673 views

Can the sum of two non-zero coprime fifth powers be powerful?

asked Dec 7, 2013 at 14:21

11 votes

0 answers

1k views

Are the twin primes the only positive double zeros of this real function?

asked Sep 9, 2013 at 12:45

11 votes

3 answers

495 views

Finite objects for which isomorphism is NP-hard or harder?

asked May 13, 2016 at 9:03

10 votes

2 answers

2k views

When are the adjacency matrices of non-isomorphic graphs similar?

asked Mar 22, 2015 at 9:41

10 votes

1 answer

377 views

Reducibility of polynomials maps

asked Dec 24, 2013 at 10:31

10 votes

3 answers

3k views

Reduction from factoring to solving Pell equation

asked Jul 21, 2011 at 16:16

10 votes

3 answers

1k views

Why is the gcd so large in an identity related to the $abc$ conjecture?

asked Aug 2, 2013 at 9:20

10 votes

3 answers

663 views

Are all integers not congruent to 6 modulo 9 of the form $x^3+y^3+3z^2$?

asked Dec 15, 2020 at 15:14

10 votes

4 answers

1k views

The smallest solution to $2^{2k}-1=\text{powerful}$

asked Jun 12, 2021 at 11:10

Stack Exchange Network

403 Questions

Examples of math hoaxes/interesting jokes published on April Fool's day?

Examples of interesting false proofs

Conjecturally unsafe RSA primes $p=27a^2+27a+7$

Which integers can be expressed as a sum of three cubes in infinitely many ways?

Interesting conjectures "discovered" by computers and proved by humans?

Can the difference of two distinct Fibonacci numbers be a square infinitely often?

Possible counterexample to a theorem assuming Lang's conjecture

Are there open problems for primes which are known for probable primes?

Is OEIS A007018 really a subsequence of squarefree numbers?

zeta(3) in terms of derivatives of zeta at 1/2 and pi

Conjecture: The number of points modulo $p$ of certain elliptic curve is $p$ or $p+2$ for $p$ of form $p=27a^2+27a+7$

A counterexample to a conjecture of Nash-Williams about hamiltonicity of digraphs?

Forbidden polynomial identities by the abc conjecture

Is deciding if one planar graph is dual to another really NP-hard (Wikipedia claim)?

Bounds for constructing $n!$ with additions, subtractions, and multiplications starting from $1$

Consequences of technically proving anything in Coq (on at least Linux) exploiting a bug? [closed]

Is the sequence $a_n=c a_{n-1} - a_{n-2}$ always composite for $n > 5$?

Is "OEIS A001935 Number of partitions with no even part repeated" efficiently computable $\mod 4$?

Infinitely many integer solutions to $X^4+Y^4-18Z^4= -16$

What CASes say about the analytic rank of rank 8 elliptic curve '457532830151317a1'

Up to $10^6$: $\sigma(8n+1) \mod 4 = OEIS A001935(n) \mod 4$ (Number of partitions with no even part repeated )

Can the sum of two non-zero coprime fifth powers be powerful?

Are the twin primes the only positive double zeros of this real function?

Finite objects for which isomorphism is NP-hard or harder?

When are the adjacency matrices of non-isomorphic graphs similar?

Reducibility of polynomials maps

Reduction from factoring to solving Pell equation

Why is the gcd so large in an identity related to the $abc$ conjecture?

Are all integers not congruent to 6 modulo 9 of the form $x^3+y^3+3z^2$?

The smallest solution to $2^{2k}-1=\text{powerful}$