Lucas sequence implementation
Your _int_tuple function does not seem to serve any real purpose. U and V are always integers (you initialize them to 1 and do only arithmetic on them afterwards). And what exactly your program will do with a Q which is e.g. a string is hard to follow, but I think it will run into the else block (Q is neither 1 nor -1) and then try to do Qk = Q, followed by Qk *= Qk which fails for almost everything but number types.

I also can't see any parts of your code which would produce a float (though I might have overlooked one).

So I would get rid of that function and return just a tuple and see what it does.