Resolves to the value of the Ramsey number R(5,5) whenever it is determined. It is known to be in the range 43–48. Informally, it is the number of people there have to be in a room that force there to be either 5 people who all know each other or 5 people, none of whom know each other. (I will extend the close date if necessary.)

Background: https://en.wikipedia.org/wiki/Ramsey%27s_theorem#Ramsey_numbers