User blog comment:Alemagno12/How strong is this function?/@comment-1605058-20171028095436

No need to apologize about short blog posts.

If I understand correctly, you are asking about s. Quite trivially, f(1)=1, f(2)=3. f(3) and higher are already undefined, since there are infinite square-free words over a three-element alphabet (see the linked article).