[R] HTML documentation is not in the expected location

[Adelchi Azzalini]

Since I have updated my Linux system, and consequently re-installed R, I 
am unable to see HTML documentation which I used to access via a web 
browser. To be more specific, my R installation is declared to be here:

 > R RHOME
/usr/local/lib/R

However, if I look at a location such as
/usr/local/lib/R/library/base/html

this contains only two entries  	

File: 00Index.html
File: R.css

Clicking on 00Index.html, it shows the full list of entries which one 
expects to see, but clicking on one of them, 'abs' say, inevitably leads 
to the message 'File not found'.

The documentation exists (at least in the text form): from within R, 
the command ?abs shows the documentation file. However its HTML version 
is not where I expect it to find ...which is where I did it find for 
many years, until the above-mentioned Linux update.

The current system is as follows:

PRETTY_NAME="Debian GNU/Linux 9 (stretch)"
NAME="Debian GNU/Linux"
VERSION_ID="9"
 > uname -a
Linux tamiso 4.9.0-3-amd64 #1 SMP Debian 4.9.30-2+deb9u2 (2017-06-26) 
x86_64 GNU/Linux

 > cat /etc/debian_version
9.0
 > gcc --version
gcc (Debian 6.3.0-18) 6.3.0 20170516

The current R installation is
R version 3.4.2 (2017-09-28) -- "Short Summer"
but the same problem existed with 3.4.1 after the system update.

When I (re-)install R, everything seems fine; no error messages are 
generated.

Can anyone tell me how to put the HTML documentation files in the right 
place?

Best regards,

Adelchi Azzalini