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 A323727 #18 Feb 03 2019 21:03:05 %S A323727 1,2,3,4,5,5,6,5,5,6,7,7,8,7,6,5,6,7,8,8,9,9,9,8,7,6,5,6,7,8,8,7,8,9, %T A323727 8,7,8,9,10,10,11,11,10,11,10,10,9,8,8,9,10,9,8,7,8,9,10,10,11,11,10, %U A323727 9,8,7,8,9,10,11,11,10,10,9,10,10,10,11,11,10,9 %N A323727 Number of 1's required to build n using +, -, *, ^ and tetration. %H A323727 Wikipedia, <a href="https://en.wikipedia.org/wiki/Tetration">Tetration</a> %H A323727 <a href="/index/Com#complexity">Index to sequences related to the complexity of n</a> %e A323727 a(14) = 7 because 14 = (1+1)^^(1+1+1)-1-1. (Note that 14 is also the smallest index at which this sequence differs from A091334.) %Y A323727 Cf. A091333, A091334, A025280. %K A323727 nonn %O A323727 1,2 %A A323727 _Robin Powell_, Jan 25 2019