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Vepir
  • Member for 6 years, 4 months
  • Last seen this week
  • Croatia
19 votes

Extending prime numbers digit by digit while retaining primality

9 votes
Accepted

Finding the formula for the ulam spiral starting with $0$ as a bijective function $U:\mathbb{N}\rightarrow\mathbb{Z×Z}$

8 votes
Accepted

Dice puzzle: pips must sum to 21

8 votes
Accepted

Significance of multiplying $-1$ by $-1$

8 votes
Accepted

How many natural number between $100$ and $1000$ exist which can be expressed as sum of 10 different primes.

7 votes

Visually stunning math concepts which are easy to explain

7 votes

A sequence with dominoes

7 votes

A sequence with dominoes

7 votes

Winning strategy in a game with the positive divisors of $10^n$

7 votes

How many primes of the form $3^n + n^3 $ exist?

7 votes
Accepted

What is the Optimal strategy to win in this game I made?

6 votes

Just using $+$ ,$-$, $\times$ using any given n-1 integers, can we make a number divisible by n? (NO bracket allowed!!)

6 votes
Accepted

Euler's Formula and Existence of Solids

6 votes

Can all natural numbers be represented as palindromes in some base $b$?

6 votes

Help me out with the sum $\sum_{n= 0}^{N-1} \frac{ \left(a-b \cos{\left(\frac{2 \pi n}{N} \right)} \right)^2}{a^2 + b^2 -2ab\cos{\frac{2\pi n}{N}}}$

5 votes
Accepted

Number $n$ such that $2^n+3^n$ has exactly $23$ prime divisors

5 votes
Accepted

How large is the area that the bug can access?

4 votes

There are infinitely many positive integers $n$ such that $\lambda(n) = \lambda(n+1)=\lambda(n+2) = +1$;

4 votes
Accepted

How many numbers are there such that its number of decimal digits equals to the number of its distinct prime factors?

4 votes

Does every number base have at least one "Baseless number"?

4 votes

For what natural $n$ does there exist a cube composed of $n$ cubes and more

4 votes

Is $a_{n+1}=\frac{a_n(a_n+n+k)}{n+1}$ eventually a non-integer, for all $k$?

4 votes
Accepted

$\sqrt{n}$ with at least five equal among the first six digits

4 votes
Accepted

Non diagonally incrementing pairing function

4 votes

Series Summation Problem $1+2+3+\dots+n=k$

3 votes

Obscuring squares of Rubik's cube

3 votes

Calculating area of triangle

3 votes
Accepted

Arbitrarily long palindromes in two consecutive number bases

3 votes

Black and white shirts puzzle

3 votes

Sum of the first $n$ palindromes