I know the general scheme for notating electronic configurations is (with s and p orbitals) [noble gas core]nsel.$n$pel. etc., where $n$ is the principal quantum number and el. is the number of electrons occupying that subshell, e.g. carbon: [He]2s22p2.
Now, how do you include hybrid orbitals? The problem arises because some hybrid orbitals already have superscript numbers (sp2, sp3 …) – how do you differentiate between these superscript numbers and those denoting how many electrons fill that orbital? If I were to write out the electronic configuration for the hybridised carbon atom in $\ce{CO2}$, this would not be a problem: [He]2sp22p2, but what about the carbon atom in $\ce{CH4}$, which has sp3 orbitals? Would you write [He]2sp3, 4 or [He]2sp34 or something else?