Dan Brumleve's user avatar
Dan Brumleve's user avatar
Dan Brumleve's user avatar
Dan Brumleve
  • Member for 12 years, 1 month
  • Last seen more than 3 years ago
216 votes
Accepted

Why can you turn clothing right-side-out?

70 votes
Accepted

Can't find the flaw in the reasoning for this proof by induction?

45 votes
Accepted

Is a prime factor of a number always less than its square root?

26 votes

Which one result in mathematics has surprised you the most?

21 votes

How, if at all, does pure mathematics benefit from $2^{74207281}-1$ being prime?

20 votes

Can every even integer be expressed as the difference of two primes?

18 votes
Accepted

Are Primes a Self-Fulfilling Prophecy?

18 votes
Accepted

Are sines of primes dense in $[-1,1]?$

18 votes

Decidability of the Riemann Hypothesis vs. the Goldbach Conjecture

16 votes

Divisibility of large number

16 votes

Infinitely many $n$ such that $n^2+1$ is squarefree

15 votes

Which simple puzzles have fooled professional mathematicians?

15 votes
Accepted

Arrangement of Numbers

13 votes
Accepted

Suppose $p$ is an odd prime. Show that $1^{p-1} +2^{p-1}+ \ldots +(p-1)^{p-1}\equiv -1\pmod p$

13 votes

Is $\sum_{n \ge 1}{\frac{p_n}{n!}}$ irrational?

12 votes
Accepted

Prove that there exist a block of $2002$ consecutive natural numbers.

12 votes

What's the closest approximation to $\pi$ using the digits $0-9$ only once?

11 votes

How to perform a fair coin toss experiment over phone?

11 votes
Accepted

For primes sufficiently large, must digit products be zero?

10 votes

What are some examples of a mathematical result being counterintuitive?

10 votes

Obtaining irrational probabilities from fair coins?

9 votes
Accepted

Find all positive integers $n$ such that $\phi(n)+\sigma(n)=2n$.

9 votes

What properties of busy beaver numbers are computable?

9 votes
Accepted

No integer solutions for $x^5 - 3y^5 = 2008$

9 votes

$-1$ as the only negative prime.

8 votes
Accepted

What is this shape ? $|x|+|y|+|z|=1$

8 votes

What is the simplest way to prove that the logarithm of any prime is irrational?

8 votes

The limit of the square root of two times the square root of two times.....

7 votes

How Many Natural Numbers Can Get Expressed as the Sum of Consecutive Natural Numbers in only One Way?

7 votes
Accepted

Even numbers greater than 6 as sum of two specific primes

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2 3 4 5
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