User blog comment:P進大好きbot/List of common mistakes on formal logic appearing in googology/@comment-30279966-20200118174447/@comment-30279966-20200119063043

In that case, I guess that supposedly Σ(20) is a computable number while Σ(10100) is not because for former we likely (intuitively) can write an explicit algorithm (or formula) of computing it on Earth while for latter we can't. I see why this definition doesn't cause trouble but it makes the boundary between uncomputable and computable numbers vague.