User blog comment:PsiCubed2/CURRENT VALUE OF PEGG/@comment-27516045-20170608203829/@comment-30754445-20170617235356

Depends on:

(1) Just how big is Loader's Number (so far, nobody really knows)

(2) How the "letters" beyond Z will be defined.

Yn should be around fψ(ψᵢ(0))(n) and beyond that it's anybody's guess.

(it's worth noting that the letters are currently well-defined only up to P for real numbers, and up to R for integers)