I have been told that resources like Mathematica's Number Recognition (which I've never tried myself) and the Inverse Symbolic Calculator (ISC) can be used to find possible closed forms for real numbers (with many known decimal digits).
But I would like to know if there are similar resources (preferably free ones) that work for rational numbers or integers (even large integers). In particular, I'm searching for some program which can:
- find "complex" ways to express a number (for example, by using particular constants or functions);
- find expressions of a number in terms of sums of squares, squares roots, cube, cube roots, sum of prime numbers, and other things.
Note: I know that Wolfram Alpha can do such things, but the limited computation time doesn't allow to have many results.