User blog comment:Alemagno12/Unthinkable numbers/@comment-31663462-20170417232155

All numbers are thinkable. Clearly, it is easy to think of all whole numbers as 1+1+1+... Personally, I'd start over with this:

Consider a formal language or system or whatever, which will be much more precise than just "what you can think of".

Consider some fancy symbols that may belong to this language.

Consider the smallest number you can't think of with n symbols in that language.

Basically how Rayo's number was made.