And again: Falsifiable (after 7 tests):
(19,409,52675715324794896384) expected (36376152090211696640,1,7) but got (36376152090211697611,1,7)

clearly the result cannot be even and mine is correct: https://www.wolframalpha.com/input?i=19*409%5E7

In initial haskel code skeleton the exported function is named incorrectly:

module Kata (arrowArea) where -- this should be 'module Kata (x) where'

x :: Int -> String
x = undefined

Tests are inaccurate:

Falsifiable (after 30 tests):
(23,241,14932274143297536) expected (9983789202489408,10,1) but got (9983789202489409,10,1)

you are multiplying two odd primes to some powers and getting even number.

I am wondering what "" represents as I am assuming that () is a Leaf.

That is probably the worst described Kata I have done.

Mind sharing which tool did you use for that? Since writing FSM is pretty easy however manual conversion doesn't sound appealing.

The issue is that when they throw it in the part I xxxed out they show literal formula that solves the problem. You can just copy paste it and it works. By the way I have a working solution to this problem so I am commenting only after I solved it.

Haskell

test/Codewars/Kata/SequencesSpec.hs:19:33: error:
    • Couldn't match expected type ‘Integer’ with actual type ‘Int’
    • In the second argument of ‘shouldBe’, namely ‘xxxxxxxx’ -- here was solution
      In the expression: getScore x `shouldBe` xxxxxxxx -- same here
      In the second argument of ‘($)’, namely
...

When tests fail then output something like - test of \x shouldReturn which should be fixed.

Tests are failing weirdly not marking my victory correctly:
there are 15 cakes on the table; you decide to go first
your turn: there are now 15 cakes on the table; you eat 1 cake
my turn: there are now 14 cakes on the table; I eat 3 cakes
your turn: there are now 11 cakes on the table; you eat 1 cake
my turn: there are now 10 cakes on the table; I eat 2 cakes
your turn: there are now 8 cakes on the table; you eat 1 cake
my turn: there are now 7 cakes on the table; I eat 3 cakes
your turn: there are now 4 cakes on the table; you eat 1 cake
my turn: there are now 3 cakes on the table; I eat 3 cakes
your turn: there are now 0 cakes on the table; you eat 0 cakes