New posts in recreational-mathematics

Is every natural number the truncation of a prime?

How to estimate the number of articles on Wikipedia using the "random article" function?

Is there a list of the number of sets of consecutive integers that sum to n?

Five Similar Triangles from 4-5-6

Arranging numbers from $1$ to $n^2$ in a $n\times n$ board

A card game with no decisions

Defining $|x|=-1$

Generating numbers by repeated doubling and digit reversal

Functional Equation $f(x+y)-f(x-y)=2f'(x)f'(y)$

Does every number not ending with zero have a multiple without zero digits at all?

Relationship between primes and practical numbers

Can we arrange $\{1,...,16\}$ in $4\times 4$-grid so {products of rows} = {products of columns}?

Identifying 2 poisoned wines out of 2^n wines

Cyclic sums -- How do you use them?

Lights out game on hexagonal grid

The number of prime years in a lifetime

Behaviour of the series $\exp_p(x)=\sum_{k=0}^{\infty}\frac{x^k}{(k!)^p}$ depending on $p\approx 2$?

Optimal stopping of a Poisson Process with a risky reward

Can exist an even number greater than $36$ with more even divisors than $36$, all of them being a prime$-1$?

Prove $\sum_{n=1}^\infty(e-\sum_{k=0}^n\frac1{k!})=1$