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 A137253 #3 Nov 16 2017 15:52:24 %S A137253 4,6,9,22,33 %N A137253 Semiprimes (A001358) which are not the sum of two semiprimes. %C A137253 Apparently the list is complete. %Y A137253 Cf. A001358. %K A137253 fini,full,nonn %O A137253 1,1 %A A137253 _Zak Seidov_, Mar 11 2008