Can't install R (r-base) on 14.04

Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
r-base : Depends: r-base-core (>= 3.2.4-revised-1trusty0) but it is not going to be installed
Depends: r-recommended (= 3.2.4-revised-1trusty0) but it is not going to be installed
Recommends: r-base-html but it is not going to be installed
r-base-dev : Depends: r-base-core (>= 3.2.4-revised-1trusty0) but it is not going to be installed
Depends: gfortran but it is not going to be installed
Depends: liblapack-dev but it is not going to be installed or
libatlas-base-dev but it is not installable
E: Unable to correct problems, you have held broken packages.