I don't know about this... doesn't this tend to infinity? Say in python, print 'x'*10000000... each zero is ten times the length yet only +1 byte

@Quintec it does! That's actually a very inefficient answer though. Would be smarter to try and do, say, TREE(3) iterations of an output. Maybe take the logarithm base 10 of the output, though.

Computing the length of the longest finite output is called the Busy beaver function. It grows faster than any computable function. Even if you take the logarithm of the output length, or super-logarithm, or divide it by Ackermann function, or any other computable postprocessing, the quotient outputlen/bytecount still tends to infinity.