User VividD - Mathematics Stack Exchange

695 votes

25 answers

72k views

Splitting a sandwich and not feeling deceived

asked Jan 14, 2014 at 5:08

111 votes

5 answers

10k views

Fibonacci number that ends with 2014 zeros?

asked Jul 19, 2014 at 22:04

99 votes

39 answers

44k views

Unusual mathematical terms

asked Jan 13, 2015 at 17:21

81 votes

2 answers

3k views

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

asked May 15, 2015 at 22:08

47 votes

3 answers

14k views

Is $n! + 1$ often a prime?

asked Jul 1, 2014 at 9:53

45 votes

5 answers

2k views

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

asked Jan 4, 2015 at 2:07

44 votes

2 answers

1k views

Only 12 polynomials exist with given properties

asked Apr 18, 2015 at 2:54

30 votes

5 answers

2k views

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

asked May 11, 2015 at 23:52

25 votes

1 answer

755 views

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

asked May 12, 2015 at 11:12

25 votes

5 answers

4k views

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

asked Aug 30, 2015 at 8:53

20 votes

3 answers

3k views

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

asked May 20, 2015 at 21:02

19 votes

1 answer

13k views

Average distance between two random points in a square

asked Apr 27, 2015 at 11:13

15 votes

5 answers

657 views

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

asked Apr 19, 2015 at 17:39

14 votes

1 answer

412 views

Is there a name for this "mean"?

asked Aug 31, 2015 at 18:54

13 votes

2 answers

2k views

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

asked Sep 5, 2015 at 14:27

12 votes

3 answers

241 views

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

asked Apr 25, 2015 at 1:34

12 votes

2 answers

2k views

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

asked Jan 5, 2015 at 20:27

12 votes

2 answers

3k views

Can you solve this captcha?

asked Oct 15, 2014 at 11:16

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)

asked Jan 6, 2015 at 0:02

11 votes

2 answers

225 views

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

asked Jan 21, 2015 at 0:15

11 votes

11 answers

2k views

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

asked Apr 28, 2014 at 12:17

11 votes

3 answers

2k views

Finding 1000th 5-smooth number

asked May 9, 2014 at 14:01

10 votes

2 answers

1k views

Do 4 consecutive primes always form a polygon?

asked Jul 10, 2014 at 20:42

10 votes

3 answers

3k views

What is golden ratio doing in this computer code?

asked Jul 15, 2014 at 9:47

8 votes

1 answer

651 views

Platonic solids and charged particles

asked Apr 30, 2014 at 13:12

8 votes

2 answers

822 views

Visual illustrations of circle packing theorem?

asked May 13, 2014 at 21:12

8 votes

1 answer

220 views

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

asked Jan 5, 2015 at 17:12

8 votes

1 answer

492 views

Numbers represented as two different sums of squares

asked Sep 30, 2014 at 7:05

8 votes

2 answers

3k views

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

asked Apr 20, 2015 at 23:43

8 votes

3 answers

879 views

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

asked May 4, 2017 at 21:33

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105 Questions

Splitting a sandwich and not feeling deceived

Fibonacci number that ends with 2014 zeros?

Unusual mathematical terms

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

Is $n! + 1$ often a prime?

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

Only 12 polynomials exist with given properties

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

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

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

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

Average distance between two random points in a square

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

Is there a name for this "mean"?

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

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

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

Can you solve this captcha?

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

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

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

Finding 1000th 5-smooth number

Do 4 consecutive primes always form a polygon?

What is golden ratio doing in this computer code?

Platonic solids and charged particles

Visual illustrations of circle packing theorem?

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

Numbers represented as two different sums of squares

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

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