Part of the reasoning of choosing it as a topic was the obscurity. It means that some of the challenge comes from only having basic information about the requirements.

Test results for first fixed test looks confusing without the quotes.
'Testing string and integer 0'
Putting the string in quotes like the random tests would solve this.

Approved

I'm not that familiar with Javascript but it looks good to me.

Some of the solutions rely on the culture being one that uses , as Thousnads seperator.

Either:

• description should say whether we need to worry about culture (deciding either way would break some existing tests)
• there should be tests theat check it works in other cultures

or just add test cases for all five remaining factorials below int32 max value.

I see a couple that would say a grid of all 5's was correct along with other false positives.

And it is retired with no feedback as to why.

If anyone knows why it was retired (I understand the process, first four people voted it down) but not the reason.

On the popup menu at the top right of the screen there is a "New Kata" option.

I found the interface relatively straight forward to use.

Make sure your Kata is a new idea first by searching the existing Kata.

There are four important sections to fill out.

1. Your (hidden) solution.
2. The template for the solution that the user starts with.
3. The sample tests the user can see and edit.
4. The hidden tests required to solve. This is usually the sample tests, plus some random tests and any interesting edge cases.

https://www.codewars.com/topics/kata-best-practices

I have just created a new C# kata https://www.codewars.com/kata/5cf8e2692ad4650001ce9b5b

It is related to the Thue–Morse Sequence.

Anyone fancy a go :)

I did a search for similar kata and found the following three that use the Thue-Morse Sequence:
https://www.codewars.com/kata/5998ce70a499a7926a0000a8
https://www.codewars.com/kata/591aa1752afcb02fa300002a
https://www.codewars.com/kata/589a9792ea93aae1bf00001c

I believe my Kata is sufficiently different that it is not a duplicate.
All the existing Kata look at the first n terms of the sequence, two creating, the third validating.
My Kata is about calculating just the nth term and has higher values of n.

C# translation tests do not check for mutation of the original list.

Why are you checking whether n is odd or even?
I think you want to check whether length s is odd or even

Are you using ToUpper and ToLower on string or char?

string uses the syntax myString.ToUpper() https://docs.microsoft.com/en-us/dotnet/api/system.string.toupper?view=netframework-4.8
char uses the syntax char.ToUpper(myChar) https://docs.microsoft.com/en-us/dotnet/api/system.char.toupper?view=netframework-4.8

Normally see this error when you do myChar.ToUpper() and therefore try to treat a char as a string