#ramsey-numbers

The problem involves Ramsey numbers

https://en.wikipedia.org/wiki/Ramsey_theory https://en.wikipedia.org/wiki/Ramsey%27s_theorem http://mathworld.wolfram.com/RamseyNumber.html https://en.wikibooks.org/wiki/Combinatorics/Bounds_for_Ramsey_numbers http://www.combinatorics.org/ojs/index.php/eljc/article/view/DS1 - "Small Ramsey Numbers" article