User blog comment:DontDrinkH20/"Interesting numbers" and the 3 Classes of Googolisms/@comment-27513631-20180813194237

Isn't \(a=S(S(0))+S(S(0))\) a complexity-3 formula defining 4? (If so, I'm pretty sure all numbers \(\leq 16\) have complexity-4 formulae.)

Equivalent defintion for interestingness: a number \(n\) is \(a\)-interesting for some \(a\leq n\) when for every \(0c(n)\) and \(c(n+d)+d>c(n)\).