This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A230875 #7 Nov 07 2013 11:57:46 %S A230875 0,1,2,2,4,4,4,4,16,16,16,16,16,16,16,16,65536,65536,65536,65536, %T A230875 65536,65536,65536,65536,65536,65536,65536,65536,65536,65536,65536, %U A230875 65536 %N A230875 a(1)=0; thereafter a(n) = 2^a(ceiling(n/2)). %C A230875 a(33) through a(64) are 2^65536. %F A230875 For n>2, a(n) = a tower of 2's of height ceiling(log_2(n))-1. E.g. a(17) = 2^2^2^2. %Y A230875 Cf. A230863, A230874. %K A230875 nonn %O A230875 1,3 %A A230875 _N. J. A. Sloane_, Nov 07 2013