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 A191772 #4 Mar 30 2012 18:57:33 %S A191772 2,6,11,12,20,21,29,31,32,33,44,46,48,49,63,65,67,68,69,71,87,90,92, %T A191772 93,94,96,107,113,118,121,123,124,125,127,128,131,142,148,155,159,161, %U A191772 162,164,166,168,171,185,191,192,197,202,206,208,209,211,212,214 %N A191772 Positions of 2 in A191770. %C A191772 See A191770. %t A191772 (See A191770.) %Y A191772 Cf. A191770, A191771, A191773. %K A191772 nonn %O A191772 1,1 %A A191772 _Clark Kimberling_, Jun 16 2011