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 A191253 #4 Mar 30 2012 18:57:31 %S A191253 4,13,19,23,32,36,45,54,60,64,73,82,88,92,101,107,111,120,124,133,142, %T A191253 148,152,161,167,171,180,184,193,202,208,212,221,225,234,243,249,253, %U A191253 262,271,277,281,290,296,300,309,313,322,331,337,341,350,354,363,372,378,382,391,400,406 %N A191253 Positions of 2 in A191250. %C A191253 See A191250. %t A191253 (See A191250.) %Y A191253 Cf. A191250. %K A191253 nonn %O A191253 1,1 %A A191253 _Clark Kimberling_, May 28 2011