TITLE: Which journals publish 1-page papers
QUESTION [20 upvotes]: Having read a thread on a similar question on expository papers I'm reminded of reason #99 to drop my math PhD thingy, late c20th: I just couldn't blow up this paper to 4 pages. (OK, one half-page calculation was left to the expert reader (and other experts could guess), but...)

REPLY [3 votes]: I just stumbled across a very recent example (2017) at the Archiv der Mathematik which I felt compelled to add to this list.