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 A089541 #3 Mar 30 2012 17:29:13 %S A089541 2,2,3,5,11,103,71,661,72577,329891,13305601,4938161,75024347, %T A089541 3790360487,186810624001,10461394944001,118562476032001, %U A089541 24343626257521,1713311273363831,117876683047,4644631106519040001,3994008464491 %N A089541 Greater prime factor of semiprimes in A089539. %Y A089541 Cf. A085747, A089538, A089539, A089540. %K A089541 nonn %O A089541 1,1 %A A089541 _Ray Chandler_, Nov 09 2003