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 A252485 #9 Dec 18 2014 02:10:03 %S A252485 144,73,12,23,14,8,15,9,7,11,6 %N A252485 Least index k for which n occurs in A161885, or 0 if n never occurs. %C A252485 Further nonzero values are a(18)=5, a(19)=4, a(26)=3, a(32)=2. %K A252485 nonn,more,hard %O A252485 4,1 %A A252485 _M. F. Hasler_, Dec 17 2014