Mathics is an open source clone of Mathematica. https://mathics.org/ https://mathics.org/ Naturally, Wolfram hired the creator and the project nearly died. A

Mathics is an open source clone of Mathematica. https://mathics.org/ 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.