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 A187473 #6 Mar 30 2012 18:57:19 %S A187473 2,4,6,8,10,12,15,16,19,21,23,25,27,29,31,34,36,37,39,42,44,46,48,50, %T A187473 52,55,57,59,61,63,65,67,69,71,73,76,78,80,82,84,86,88,90,92,95,97,99, %U A187473 101,103,105,107,109,111,113,116,118,120,122,124,126,128,130,132,135 %N A187473 Complement of A187472. %C A187473 See A187224. %t A187473 (See A187472.) %Y A187473 Cf. A187224, A187472. %K A187473 nonn %O A187473 1,1 %A A187473 _Clark Kimberling_, Mar 10 2011