I have published my first app on Google Play recently. Optimal Lottery Picker picks for you random lottery number via a custom algorithm which picks rare sequences, so that if you win, you do not have to share your gains! The app is completely free and is available for android phones!
If your lottery is not listed, you can use the “Custom Lottery” to define your own lottery with any combination!
I developed Optimal Lottery Picker mostly to learn how to code, publish and promote apps. This was my first time programming in Java (I am more used to C++ and Matlab) and it was frankly pretty straightforward coming from C++. I think the best online resource I found about it was this website (this page is about in app-billing).