"The shortest paper ever published in a serious math journal", according to [Fermat's Library][1]:

J. H. Conway and A. Soifer, [Can n² + 1 unit equilateral triangles cover an equilateral triangle of side > n, say n + ε?][2]


  [1]: https://fermatslibrary.com/
  [2]: https://fermatslibrary.com/s/shortest-paper-ever-published-in-a-serious-math-journal-john-conway-alexander-soifer