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 A168544 #2 Mar 30 2012 18:52:37 %S A168544 1,6,9,15,21,30,36,51,54,69,75,90,96,99,114,120,135,141,156,174,210, %T A168544 216,231,261,285,300,309,321,330,405,411,414,429,441,510,516,525,531, %U A168544 546,576,615,639,645,651,639,645,651,660,714,726,741,744,804,810,834,849 %N A168544 The nonprime halfs of even single (or even isolated) numbers. %Y A168544 Cf. A008486, A040040, A141468, A168497. %K A168544 nonn %O A168544 1,2 %A A168544 _Juri-Stepan Gerasimov_, Nov 29 2009