In Clojure, readability is obtained through standardization. Every Clojure programmer instantly knows what the functions in the standard library do. Because there's not much syntax in a Lisp, code is very easy to read once one knows the functions.
"filter" is incredibly useful, and most modern languages (including Java 8) have it built in.
"even?" is sometimes useful, and languages are kind of hit-and-miss about it, but its usually small enough to inline, and the biggest cost of not having it built-in is probably things like people using modulus rather than first-bit testing in Java which, IIRC, produces somewhat slower code for that check.
Python also allows for functional programming to a certain degree, but clojure is a lot more powerful when it comes to language extensions.
Threads as a library (for js environments) for clojure. https://github.com/clojure/core.async
Logic programming for clojure. https://github.com/clojure/core.logic
Declarative UI building, with dataflow semantics. http://reagent-project.github.io
Additionally immutability makes your life a lot easier. Parallel computing in clojure is a no brainer, you just change your map to pmap, and that's it.
I have always wanted to look at building something again in one of the popular FPLs.
Readability and language understanding are not separable. I for one have a hard time actually understand what the code does above (although I can guess it). But I am not sure how ^ translate into [true false false true true true false false false false ...] sequence because, I thought we were calculating oddity of 1000 numbers.
[1 2 3 4 5 6 7 8 9 10 ...] ==> [T F T T F T F T T T ]
Perhaps the lack of understanding Clojure syntax to comprehend what the code is doing.