Here are some additional links:
To participate in the Collatz Conjecture:
http://arithmetica.network/contribute#Collatz%20Conjecture
To define a new problem for others to work on:
http://arithmetica.network/contribute
These links point to the version of Arithmetica that was submitted to ETHDenver. Since then , we have been working on refactoring and coming up with a scalable solution for saving state.
The project is open source and anyone is welcome to contribute, or fork. We welcome any questions/feedback.