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3x+1@home is a distributed non-profit project trying to find 3x+1 conjecture stopping time records. The 3x+1 conjecture is also known as Collatz conjecture.

The collatz conjecture: Take any positive integer N. If its even, divide it by 2. If its odd, multiply it with 3 and add 1. Repeat step 2 until the number 1 is reached. The Collatz conjecture is: For any positive integer the process above will reach the number one.

Some examples:

5 -> 16 -> 8 -> 4 -> 2 -> 1 Reached the number one in 5 steps. Stopping time is 5.

18 -> 9 -> 28 -> 14 -> 7 -> 22 -> 11 -> 34 -> 17 -> 52 -> 26 -> 13 -> 40 -> 20 -> 10 -> 5 -> 16 -> 8 -> 4 -> 2 -> 1 Reached the number one in 20 steps. Stopping time is 20.

What is the stopping time (delay)? The stopping time is equal to the number of steps needed to reach the number one.

What is 3x+1@home searching for? 3x+1@home is searching for high stopping times. Obviously huge integers have high stopping times, so what we are searching for is a high n=Stopping time/Log2(N). If N has an infinite stopping time, the application will also notice this. A huge range of integers has already been checked by various projects, there is no need to check them again. This project is checking huge integers (N > 21000) that most likely haven't been checked before.

Is 3x+1@home checking for strength, completeness, etc? No. The application is optimized to calculate stopping times as fast as possible.

The result of the project can downloaded at: [http://allprojectstats.com/collatz/]

By now, the project Collatz Conjecture continues the work of 3x+1.

Erde.png 3x+1@home
Start 2008
End 2008
Status finished
Admin Markus Tervooren
Institution Team Allprojectstats.com
Country International
Area Mathematics
Info.png Apps
Win.png Win Collatz sieve 1.01
Linux2.png Linux Collatz search 1.07
Collatz sieve 1.02
Macos.gif Mac Collatz sieve 1.01
Amd64.jpg 64bit Optimized collatz search application 1.02
Collatz sieve 1.03
Ps3.png PS3
Ati.jpg ATI
Cuda.jpg CUDA
Intel.jpg Intel
Android.png Android No.gif
Raspberri Pi.png RPi No.gif
Nci.jpg NCI No.gif
Specs.png System-Specs
VRAM SP No.gif DP No.gif
RAM 116kb
Runtime 1:15h
Traffic dl/ul
Deadline 4-60 days
Checkpoints X.gif