This is the exponential function, 2^x. Where the independent variable is the number of walls jumped. For instance, after 30 jumps, your score/tile reads 1073741824, or 2^30.
Or it's the logarithmic function lg(x), where the independent variable is the score and the dependent variable is roughly proportional to the number of times you've clicked.
Well yes, logbase2(x), where x is your score, does equal the number of wall jumps. But that doesn't account for how the game is laid out. Your score is a result of the number of jumps you've made. The number of jumps you've made is not the result of your score. Therefore, despite these two functions being the inversely related, the correct relationship is 2^x. That is just my opinion though.
Sure, score = 2^walls iff log_2(score) = walls. So, being equivalent statements, one alone can not be correct.
However, as you said, one choice of describing the relationship is certainly more natural. The exponential description assigns a score to every natural number. While the logarithmic description does not.
I would interpret correct in the way that it is sometimes said, "the correct way to think about X is..." which doesn't say other ways of thinking are wrong, but limited or not illuminating.
Or maybe exponential if you consider your score to be 2^(number of walls you've jumped).
I don't get logarithmic, though.