User blog comment:Mush9/Beyond BIG FOOT (ideas in comments)/@comment-172.58.107.79-20161108023816/@comment-24920136-20161108025935

Uncomputable just means that there isn't an algorithm that can compute it. ie, given an uncomputable function U we have no method of knowing in advance what U(n) is for arbitrary n. ( Even if checking for specific U(n) values is possible )