I think it really depends what kind of mathematical exploration you want to do. If you are interested in something similar to Mathematica or Matlab, then proba

I think it really depends what kind of mathematical exploration you want to do. If you are interested in something similar to Mathematica or Matlab, then probably Python, because it is used as a language in SageMath: https://www.sagemath.org/ https://www.sagemath.org/ If you're interested in numerical computing, then there might be other choices such as Julia. If you're interested in theory programming languages, logic or category theory, then Haskell or even more esoteric language (theorem prover) like Coq or Lean could be interesting for you.