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VividD
  • Member for 10 years, 5 months
  • Last seen more than 3 years ago
695 votes
25 answers
72k views

Splitting a sandwich and not feeling deceived

111 votes
5 answers
10k views

Fibonacci number that ends with 2014 zeros?

100 votes
39 answers
43k views

Unusual mathematical terms

81 votes
2 answers
3k views

Visual proof of $\sum_{n=1}^\infty \frac{1}{n^4} = \frac{\pi^4}{90}$?

46 votes
3 answers
14k views

Is $n! + 1$ often a prime?

45 votes
5 answers
2k views

Is ${F_{n}}^2 - 28$ always a composite number?

44 votes
2 answers
1k views

Only 12 polynomials exist with given properties

30 votes
5 answers
2k views

Which is bigger: $(\pi+1)^{\pi+1}$ or $\pi^{\pi+2}$?

25 votes
1 answer
755 views

Peculiar locations of the root and the maximum of $(x+1)^{x+1}-x^{x+2}$

25 votes
5 answers
4k views

What is the probability that a natural number is a sum of two squares?

20 votes
3 answers
3k views

Probability of $ax^2 + bx + c = 0$ having real solutions

19 votes
1 answer
13k views

Average distance between two random points in a square

15 votes
5 answers
654 views

Solve the system $ x \lfloor y \rfloor = 7 $ and $ y \lfloor x \rfloor = 8 $.

14 votes
1 answer
412 views

Is there a name for this "mean"?

13 votes
2 answers
2k views

The last (and the weirdest) problem from Chen`s "Brief Introduction to Olympiad Inequalities"

12 votes
3 answers
241 views

Divisibility of $6^{2^n}+ 8^{2^n} +12^{2^n}+14^{2^n}+16^{2^n}+18^{2^n} +24^{2^n} +28^{2^n}+42^{2^n}$

12 votes
2 answers
2k views

$e^{\pi\sqrt N}$ is very close to an integer for some smallish $N$s. What about $\pi^{e\sqrt N}$?

12 votes
2 answers
3k views

Can you solve this captcha?

11 votes
1 answer
375 views

Prove or disprove that ${F_{n}}^2 + 41$ is always a composite (if $F_{n}$ is $n^{th}$ Fibonacci number)

11 votes
2 answers
225 views

If $3^x$ and $5^x$ are both integers, is $x$ an integer?

11 votes
11 answers
2k views

A function such that $f(f(n)) = -n$?

11 votes
3 answers
2k views

Finding 1000th 5-smooth number

10 votes
2 answers
1k views

Do 4 consecutive primes always form a polygon?

10 votes
3 answers
3k views

What is golden ratio doing in this computer code?

8 votes
1 answer
647 views

Platonic solids and charged particles

8 votes
2 answers
818 views

Visual illustrations of circle packing theorem?

8 votes
1 answer
220 views

Prove or disprove that ${F_{n}^2} + 43$ is always a composite

8 votes
1 answer
491 views

Numbers represented as two different sums of squares

8 votes
2 answers
3k views

If for a polynomial $P(k) = 2^k$ for $k = 0, 1, . . . , n$, what is $P(n+1)$?

8 votes
3 answers
874 views

Solving math captcha involving a limit and $\sin(1/x)$