As a French high-schooler/undergrad, I learned about Bertrand series ("séries de Bertrand"), the things of the form $$ \sum_{n=2}^\infty \frac{1}{n^\alpha \log^\beta n} $$
as part of the curriculum. They are considered standard, and there is a Wikipedia page devoted to them (and the results and proofs about their convergence). Since they appear quite often in (counter)examples, I'd argue this is for a good reason.
However, as far as I can tell, they are much less common and known in the US (and the UK?). Even on this very website, they appear to be unknown by and large (from a large majority of newcomers), and there is no mention of them on Wikipedia (let alone a page entry for them).
Is there a reason why? Are they not considered useful, or is it that they are known but "the Internet" somehow doesn't reflect this?