it was such obvious, but I didn't guess to this solution :(

some of you saying that you are dumb cuz you cant solve in this way, this is Math formula

I felt so smart and now I feel dumb. This is the way.

hacker

well, this kata has loop tag

Maybe 'cause there is another one identical but from 2 years prior just below the top one?

🏆😎

I agree. I'm new here and I'm still working on all the low hanging fruit. Most of the top answers I've seen so far have been one liners (and very enlightening). I was shocked this solution wasn't at the top of the list. Even people who aren't programmers know there's a formula for summation (no offense). This was my first upvote for best practice.

Hey, thanks!

This solution should be voted as the best practice. I feel dumb my first solution used a loop.