Let $f(n)$ be the maximal $k$ such that there exist integers $1 \le a_1 < \dotsc < a_k \le n$ such that all sums of the shape $\sum_{u \le i \le v} a_i$ are distinct. It is known that $f(n) \geq (2+o(1))\sqrt{n}$. Source: See comment by Desmond Weisenberg here: https://www.erdosproblems.com/forum/thread/357.