User blog comment:PsiCubed2/CURRENT VALUE OF PEGG/@comment-27516045-20171103012553/@comment-30754445-20171107201843

Letter notation does not use the letter I and O, due to their visual similarity with the digits 1 and 0. So there's no such number as "I5.8".

You can learn more about this notation here:

Parit I (E to H)

Part II (J to N)

Part III (P)

Definitions for Q and above will also be posted... eventually

(PEGG probably won't get to Q before 2020)