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 A089532 #3 Mar 30 2012 17:29:13 %S A089532 4,6,7,10,12,13,18,24,25,29,33,35,42,45,50,55,59,60,66,68,70,77,78,79, %T A089532 87,88,89,100,102,104,113,123,126,127,135,136,139,142,152,158,159,165, %U A089532 169,172,176,184,187,189,197,199,201,203,209,211,216,234,237,244,251 %N A089532 A089531 indexed by A000040. %F A089532 a(n)=k such that A089531(n)=A000040(k). %Y A089532 Cf. A023204, A089530, A089531. %K A089532 nonn %O A089532 1,1 %A A089532 _Ray Chandler_, Nov 07 2003