To that end, my K version can be tweaked slightly to work with oK, an open-source interpreter based on k6:

    {(x;"Buzz";"Fizz";"FizzBuzz")@2 2/~3 5!\:x}'1+!20

k6 swapped the argument order of "mod" and made change of base into an overload of "/", rather than a named builtin. See it in action here:

http://johnearnest.github.io/ok/index.html?run=%20%7B%28x%3B...