Collatz conjecture

Etymology
Named after, who first proposed it in 1937.

Proper noun

 * 1)  The conjecture that the process of taking a number $$n$$ and, if $$n$$ is even, dividing it by 2, or if $$n$$ is odd, multiplying it by 3 and adding 1, then repeating this process, will eventually yield 1.

Translations

 * Icelandic: tilgáta Collatz