User ViHdzP - Mathematics Stack Exchange

22 votes

Is there a prime every year if YYYYMMDD is treated as a base-$10$ number?

answered Dec 27, 2019 at 5:22

12 votes

Accepted

Is this sequence based on the Fibonacci numbers a prime generator?

answered Jan 5, 2020 at 21:27

10 votes

Accepted

Find the smallest integer $n>1$ such that $\frac{1}{n}\left(1+2^2+3^2+\ldots+n^2\right)$ is a perfect square

answered Oct 27, 2019 at 17:59

9 votes

Accepted

Please explain the proof of the Mutilated Chessboard Problem

answered Nov 1, 2019 at 3:50

9 votes

Absolute convergence to a rational number

answered Dec 25, 2019 at 2:05

9 votes

Accepted

Formula for the area of a rhombus

answered Oct 4, 2020 at 7:00

8 votes

Accepted

A quadrilateral inscribed in a rectangle

answered Dec 27, 2019 at 6:06

8 votes

Accepted

Intuition behind Diophantine approximation: why do we express the bound as function of denominators?

answered Oct 28, 2019 at 0:56

7 votes

Accepted

Solving Strong Mathematical Induction Sequence

answered Nov 4, 2019 at 3:42

7 votes

Accepted

What is $n$ if $\frac{1+3+5 \cdots+ (2n-1)}{2+4+6+ \cdots 2n}=\frac{2017}{2018}$?

answered Dec 26, 2019 at 0:12

7 votes

Accepted

Find all integers $m,\ n$ such that $m^2+4n$ and $n^2+4m$ are both squares.

answered Dec 19, 2019 at 6:50

7 votes

Accepted

I heard there are 48 regular polyhedrons. With what Jan Misali calls regular polyhedrons, are there any more?

answered Aug 6, 2020 at 1:09

6 votes

Find all solutions in $\mathbb{N}$ to $a^a=a^b+b^a$

answered Jan 5, 2020 at 19:46

6 votes

Growth rate of a divisor function

answered Mar 6, 2020 at 7:23

6 votes

Accepted

Moving counters on a chessboard

answered Dec 3, 2019 at 23:14

6 votes

Accepted

Positive integer sequence with terms that are multiples

answered Dec 27, 2019 at 21:09

5 votes

Proof that $n^3 \leq 2^n$ for $n \geq 10$ by induction

answered Dec 29, 2019 at 22:47

5 votes

Accepted

Is $(1-i)^5 = 2-2i$?

answered Dec 28, 2019 at 22:36

5 votes

Accepted

The sum of оbtuse angles of а convex polygon is $2013^\circ$. How many sides does it have?

answered Dec 25, 2019 at 20:53

5 votes

Accepted

Pigeonhole principle.

answered Dec 24, 2019 at 23:18

5 votes

A string is chosen uniformly at random from the set of all binary strings of length n. Show that the expected number of zeroes is n/2

answered Dec 9, 2019 at 17:46

5 votes

Accepted

Proving $2+2^2/2+2^3/3+2^4/4+\cdots=0$ elementarily

answered Jan 6, 2020 at 1:47

4 votes

If $x$ is irrational, is $2x - \frac{1}{x}$ irrational?

answered Dec 7, 2019 at 2:09

4 votes

A function with a point of slope of exactly $2$

answered Dec 25, 2019 at 5:26

4 votes

Accepted

How many real solutions $(x,y)$ for $x + y^2 = y^3 $ and $y + x^2 = x^3$

answered Dec 25, 2019 at 19:20

4 votes

HAPPY NEW YEAR $2020$ Remainder Problem

answered Dec 31, 2019 at 19:00

4 votes

Accepted

Factoring $F_{1001}$

answered Oct 28, 2019 at 2:06

4 votes

Accepted

Extra lottery numbers

answered Nov 18, 2019 at 1:16

4 votes

Accepted

Non-self-intersecting "Robot Walks"

answered Dec 3, 2019 at 5:46

4 votes

I can't understand how probability makes sense

answered Nov 22, 2019 at 19:43

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172 Answers

Is there a prime every year if YYYYMMDD is treated as a base-$10$ number?

Is this sequence based on the Fibonacci numbers a prime generator?

Find the smallest integer $n>1$ such that $\frac{1}{n}\left(1+2^2+3^2+\ldots+n^2\right)$ is a perfect square

Please explain the proof of the Mutilated Chessboard Problem

Absolute convergence to a rational number

Formula for the area of a rhombus

A quadrilateral inscribed in a rectangle

Intuition behind Diophantine approximation: why do we express the bound as function of denominators?

Solving Strong Mathematical Induction Sequence

What is $n$ if $\frac{1+3+5 \cdots+ (2n-1)}{2+4+6+ \cdots 2n}=\frac{2017}{2018}$?

Find all integers $m,\ n$ such that $m^2+4n$ and $n^2+4m$ are both squares.

I heard there are 48 regular polyhedrons. With what Jan Misali calls regular polyhedrons, are there any more?

Find all solutions in $\mathbb{N}$ to $a^a=a^b+b^a$

Growth rate of a divisor function

Moving counters on a chessboard

Positive integer sequence with terms that are multiples

Proof that $n^3 \leq 2^n$ for $n \geq 10$ by induction

Is $(1-i)^5 = 2-2i$?

The sum of оbtuse angles of а convex polygon is $2013^\circ$. How many sides does it have?

Pigeonhole principle.

A string is chosen uniformly at random from the set of all binary strings of length n. Show that the expected number of zeroes is n/2

Proving $2+2^2/2+2^3/3+2^4/4+\cdots=0$ elementarily

If $x$ is irrational, is $2x - \frac{1}{x}$ irrational?

A function with a point of slope of exactly $2$

How many real solutions $(x,y)$ for $x + y^2 = y^3 $ and $y + x^2 = x^3$

HAPPY NEW YEAR $2020$ Remainder Problem

Factoring $F_{1001}$

Extra lottery numbers

Non-self-intersecting "Robot Walks"

I can't understand how probability makes sense