I'm going to give you a few general hints, which applies to ALL problem solving challenges like this.
"Start with the extremes": Instead of starting for a generic N, maybe start with 1.

If you havent already, try getting out a pen and paper, and workout a few examples, and try and spot a pattern. Also, you are tasked to find the value for f(n), so try to be deliberate on this "intermidiate" value. Keep this in your mind, when looking for patterns.

Anymore than this, unfortunately will give away too much, and I don’t want to rob you of the satisfaction when you finally solve this!

👌

Nice solution :)

thx😉

👍

😎

I'm glad you think so 🙂

Brilliant solution.

Yep, seems like we approached it similarly

We both applied the same logic for regex match 😎

Thank you so much for sharing your thoughts. As someone with limited experience in this field, your comments inspire me to continue progressing and further develop my skills 🙂

Your solution is better than mine as it doesn't have to utilise an extra parameter. Well done!
Higher-level katas are quite often based on a recursive approach and this is why I wanted to judge your ability in this subject.

I'm currently reviewing your solution, and I find your approach that integrates both regular expressions and recursion much more interesting. I would never have thought of such a thing, it's truly clever.

Try to solve it recursively 😎