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 A100509 #3 Apr 19 2016 01:07:34 %S A100509 216,1149984,365727111552,1590733122516339863159808000 %N A100509 Primitive prime power perfect numbers: A096290, with multiples of earlier numbers excluded. %Y A100509 Cf. A096290. %K A100509 nonn %O A100509 1,1 %A A100509 _Yasutoshi Kohmoto_, Nov 24 2004