Where to download previous versions of R for mac?

Question

Here we find 'old' versions of R (from 2.0.1 to 2.7.0).

Here we can find the current version (3.6.3)

Where can we download the versions in between? (i.e. not the newest version, but not 'old')

Answer 1

https://cran.r-project.org/bin/macosx/old contains dmg, pkg and tar.gz files (thanks @MrFlick)

Source files can be found at https://cran.r-project.org/src/base/R-3/ for 3.x and https://cran.r-project.org/src/base/R-2/ for 2.x