This is beautiful

Please mark case 2 more clearly. It is ambiguous whether or not the |B_{k}| term is inside the denominator or just multiplied by (\frac{1}{2}).
Problem code:

• \bg_green f(k) = 1/2 |B_k| (2\pi)^{k} / k!

Proposed solutions:

• \bg_green f(k) = (1/2) |B_k| (2\pi)^{k} / k!
• \bg_green f(k) = \frac{1}{2} |B_k| (2\pi)^{k} / k!

The haskell tests use tabs instead of spaces, here's the STDerr:

test/Codewars/Kata/GrannySpec.hs:15:9: warning: [-Wtabs]
Tab character found here, and in 19 further locations.
Please use spaces instead.
|
15 | ["A1", "A2", "A3", "A4", "A5"]
| ^^^^^^^^

@Chrono79: Haskell. I can't access the numbers in the submission test.

@hobovsky: When I prioritised monotone numbers over almost-big numbers, the test for "should handle upcoming big numbers" failed. When I reversed this order, the test for monotone numbers failed.