is there a way for a possible solution without recursion?

Values from 0 to 200 will be checked

The random tests only go up to 20.

I would suggest using random.choice in main tests.

y = random.choices(range(1, 21), k=random.randint(5, 9))

instead of

y = list(set([random.randint(1, 15) for i in range(20)]))

Ruby translation: https://www.codewars.com/kumite/5fe6342121683a0021e3adee/edit

Why not a decoder as well as an encoder?

The algorithm for that can be as elegant as for the encoder.