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 A028506 #6 Feb 06 2020 00:28:19 %S A028506 1,2,4,10,24,68,198,656 %N A028506 Number of non-descending integral vectors b of length n such that number of symmetric 0-1-matrices A of order n with row sums <= b is odd. %C A028506 Is this the same sequence as A029893? - _Sean A. Irvine_, Feb 05 2020 %H A028506 Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a028/A028506.java">Java program</a> (github) %K A028506 nonn,more %O A028506 1,2 %A A028506 TORSTEN.SILLKE(AT)LHSYSTEMS.COM %E A028506 a(7) and a(8) from _Sean A. Irvine_, Feb 05 2020