# Collatz, Lothar

## The 3n+1 conjecture ★★★

Author(s): Collatz

\begin{conjecture} Let $f(n) = 3n+1$ if $n$ is odd and $\frac{n}{2}$ if $n$ is even. Let $f(1) = 1$. Assume we start with some number $n$ and repeatedly take the $f$ of the current number. Prove that no matter what the initial number is we eventually reach $1$. \end{conjecture}

Keywords: integer sequence