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 A023629 #4 Mar 30 2012 18:55:53 %S A023629 1,4,5,7,8,12,13,17,18,20,21,23,24,28,29,31,32,34,35,39,40,44,45,49, %T A023629 50,52,53,55,56,60,61,65,66,70,71,73,74,76,77,81,82,84,85,87,88,92,93, %U A023629 95,96,98,99,103,104,108,109,113,114,116,117,119,120,124,125,127 %N A023629 a(n) = c([ n/2 ]) + n, with a(1) = 1, c = complement to a. %K A023629 nonn %O A023629 1,2 %A A023629 _Clark Kimberling_