New posts in recreational-mathematics

The $n$ Immortals problem.

Class of integrals: $I(a)=\int_0^\infty \frac{dx}{e^x+ax}$

Question about a program generating palindromic prime numbers

What are the symmetries of a colored rubiks cube?

Calculate moment of inertia of Koch snowflake

Evaluation of a continued fraction

Intuitive/heuristic explanation of Polya's urn

Non-trivial "I know what number you're thinking of"

Is there a real-valued function $f$ such that $f(f(x)) = -x$? [duplicate]

Something interesting that I found about some numbers - and would like to see if it's known

New Year Maths $2019$

9 pirates have to divide 1000 coins...

A riddle for 2015

Finding an invisible circle by drawing another line

Which is greater, $20 \uparrow\uparrow\uparrow\uparrow 20$ or $4 \uparrow\uparrow\uparrow\uparrow\uparrow 4$?

New Year Maths 2018: $\color{green}{\binom ab+\binom bc+\binom cd}+\color{orange}{\binom de+\binom ef+\binom fg+\binom gh}=\color{red}{2018}$

Mathematical Intuition Behind Schizophrenic Numbers?

Upside-down equation: algebra puzzle

Dudeney's "Puzzles and Curious Problems": 55 : Eliza's Surname

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