Tough. Learned a lot.

To make it a 4kyu challenge, I suggest to add this test case: (5_599_653, 4_300_533_504)

Brilliant implementation. Can't think of any better way to solve this.

Love this kata.
If anyone can come up with a mathematical solution, I'd be highly interested.

Turns out to be a math challenge, rather than programming. Very challenging test suite.

I agree.

Great kata! Touches a couple of side problems. I learned something.

Implemented a deterministic solution with complexity O(n^3) in Python. Solves 70-by-70 puzzles in <10s on my laptop.

Nice game. This is 5% coding, 95% thinking.

Great kata. Sounds simple, turns out to be very challenging.

Thanks.
CONTIGUOUS. There is only one 2 next to 3.

Sorry, I don't understand the example {2,2,2,3}.
If subarray {2} is counted three times, why is {2,3} only counted once?

(unfortunately, the answer to nekoman's question is hidden)

Well done!
I'm not a big fan of regex, but this demonstrates it can help to concentrate on the essential stuff, leaving all the tokenization on a single line.

Perfect iterators!
I think four conditions should cover everything.
In order not to miss anything, shouldn't the exceptions be caught around each condition separately?

https://oeis.org/A002326