There is of course a FOSS rewrite https://mathics.org. - Source: Hacker News / 8 months ago

If you know Mathematica syntax, you could also try Mathics: https://mathics.org. - Source: Hacker News / about 1 year ago

I applaud calling the language Mathematica, despite Stephen Mathematica's attempts to rename it a couple of years ago. See also: https://mathics.org/ It's a more mature and complete reimplementation of Mathematica, though still miles behind the original. - Source: Hacker News / almost 2 years ago

Mathis is an open source clone of Mathematica. https://mathics.org/ Naturally, Wolfram hired the creator and the project nearly died. A couple of heroes stepped in to create a second generation, but it's just too hard to continually compete with a multi-billion dollar company. No idea how OEIS is involved. - Source: Hacker News / almost 2 years ago

There's Mathics, a subset of the language implemented in Python, but unfortunately after the main author of that was hired by Wolfram, the project seems to have basically died. Still fun for what it is. https://mathics.org/. - Source: Hacker News / over 2 years ago

Whoa, good to know that Henri Cohen was involved in this story. He is the co-creator of PARI/GP, the algorithmic number theoretic C library that I used for my thesis (https://pari.math.u-bordeaux.fr/) as well as four books in Springer's Graduate Texts in Mathematics (GTM 138, 193, 239 and 240 - most mathematicians achieve fame with just one book in this series). - Source: Hacker News / over 1 year ago

Interesting, the first time I read or heard about the PARI/GP language (mentioned in the book's preface plus introduction in Appendix C). https://pari.math.u-bordeaux.fr/. - Source: Hacker News / about 2 years ago

This is one I'm aware of, I don't have any previous experience with it though. https://pari.math.u-bordeaux.fr/. Source: about 3 years ago