# Collatz

Last updated 2014-04-10 11:32:56 SGT
1. box.
2. a
3. conducting
4. in
5. involving a
6. suggested
7. found out;
8. cat
9. experiments
10. she took
11. who once
12. the ethics committee,
13. of mine
15. at this,
17. told us stories
18. immediately
19. a professor
20. tipped off
21. a friend
22. ordeal over a
23. offense
24. telling them
25. My professor
26. She said she
27. I know
28. and
29. One day,
30. of his friend's

The Collatz conjecture is an open question about how numbers relate to each other. Take any natural number $n_0$; if $n_0$ is odd, let $n_1$ be $3n_0+1$; otherwise let $n_1$ be $n_0/2$. Define $n_2$ by doing the same to $n_1$, and so on. We conjecture that for any starting number $n_0$, the sequence of $n$'s eventually reaches some $i$ such that $n_i=1$. Is this true or not? Nobody knows.