Nice to see some experimentation. :) I tested all 2^31 non-negative integers, which is 2147483648 values. If I remember correctly, the value that was wrong was

Nice to see some experimentation. :) I tested all 2^31 non-negative integers, which is 2147483648 values. If I remember correctly, the value that was wrong was large, probably between 2^30 and 2^31. Java is pretty fast and I think this took tens of minutes. Python is about 20 times slower so it may take hours for you.