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 A308611 #11 Aug 23 2019 13:11:45 %S A308611 6,12,15,20,35,56,63,77,99,143,208,221,272 %N A308611 Numbers k such that A307616(k) > A307616(k-1). %K A308611 nonn,more %O A308611 1,1 %A A308611 _Jack Zhang_, Jun 10 2019 %E A308611 a(11)-a(13) from _Michel Marcus_, Jun 11 2019