User blog:MilkyWay90/I'm ready for the easiest OCF!

I am ready to start learning the easiest OCF!

I have learned about finite parameter multi-variable Phi function (phi(1, 1, 0) = the limit of gamma_n), and the definition of an uncountable ordinal (an ordinal where there is no function f(n) where for every element in the ordinal (y), there will be a value f(x) = y where x is a natural number)

So I am ready to start learning (the easiest) OCFs!

So can somebody give a link/definition in the comments to whichever OCF is easiest to learn in their opinion?