In that book published in 1963
there’s a full listing in Fortran for composing music based on stochastic principles.
The book is available on Google book
The code is now on Github:
How to compile:
How the program work is explained here:
Ronald Squibbs, “6. Iannis Xenakis’s Free Stochastic Music Program as an Aid to Analysis” in Kanach, Sharon, and Peter Nelson, eds. 2024. Meta-Xenakis: New Perspectives on Iannis Xenakis’s Life, Work, and Legacies. 1st ed. Cambridge, UK: Open Book Publishers.
Here’s a result, “ST/10=1,080262”, by “Ensemble de Musique Contemporaine de Paris”
- ST for stochastic
- 10 for ten instruments
- 080262: this was first computed by an IBM 7090 the 8th of February 1962
[Edit] I wasn’t convicted this piece has his place in the “Music is the best” thread 
[/Edit]
Finally a quote from John Backus, the father of Fortran:
Well, don’t go into software. It’s just such a complicated mess that you just frazzle your brains trying to do anything worthwhile.
All my sources comes from this post in French: