The Farey sequence problem seen at https://www.freecodecamp.org/learn/coding-interview-prep/rosetta-code/farey-sequence explains to us that it’s a “sequence of completely reduced fractions between
1 which, when in lowest terms, have denominators less than or equal to
n , arranged in order of increasing size.”
This is fine, but the tests for n=4 and n=5 expects us to return, along with the other reduced fractions, the fraction 2/4, which is not completely reduced. This could be changed to follow the rules presented.
Even the explanation provides the sequences without the fraction 2/4.