Macsyma
Macsyma is a computer algebra system that was originally developed from 1967 to 1982 at the MIT AI Lab and Project MAC. In 1982, Macsyma was licensed to Symbolics, and a commercial version of Macsyma based on this licensed version is still available. There is also an open source version, called Maxima, which is based on the 1982 version of Macsyma which was placed in a software library at the United States Department of Energy, which was a major sponsor of the project.