- #1

- 150

- 10

$$\sum_{k=1}^{n} k= 12345...n$$

I'm sure this is actually something trivial that has been defined before, but I was finding it really difficult to search it up on Google (apparently "addition but instead of adding numbers just clomp together" doesn't yield very good results). So yeah, if anyone can tell me a better way to name this sort of maths it'd be greatly appreciated.