# What mathematical conjecture do you know of that is the easiest to explain, but the hardest to attempt a proof of?

##### 1 Answer

Feb 29, 2016

#### Answer:

I would say Lothar Collatz's conjecture, which he first proposed in 1937...

#### Explanation:

Starting with any positive integer

If

#n# is even then divide it by#2# .If

#n# is odd, multiply it by#3# and add#1# .

The conjecture is that regardless of what positive integer you start with, by repeating these steps you will always eventually reach the value

For example, starting with

#7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1#

If you would like to see a longer sequence, try starting with

This conjecture has been tested for quite large numbers. It looks like it is true, but there is no effective way of solving it with our current mathematical techniques as far as we can tell.