Is there a version of BOINC for Raspberry Pi? The app is actually named solo_collatz_6.00_arm-android-linux-gnu so it would stand to reason that if Pi runs an ARM Linux distro, it may work.
[Edit: Nope. I read some more and it will not work with the android app as that is for an ARMv7 processor and the Pi is an ARMv6 processor].