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 A190393 #19 Mar 13 2022 09:45:31 %S A190393 1,2,6,24,120,144,28,1408,2025,86400,1782,1092096,4186,31360, %T A190393 241920000,23953408,140692,114108912,1092690 %N A190393 Number of ways to place n nonattacking nightriders on an n X n toroidal board. %C A190393 A nightrider is a fairy chess piece that can move (proportionate to how a knight moves) in any direction. %H A190393 Vaclav Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Number of ways of placing non-attacking queens, kings, bishops and knights</a> (in English and Czech). %Y A190393 Cf. A172141, A173429, A051906. %K A190393 nonn,nice,hard,more %O A190393 1,2 %A A190393 _Vaclav Kotesovec_, May 10 2011 %E A190393 Terms a(16)-a(17) from _Vaclav Kotesovec_, May 14 2011 %E A190393 Terms a(18)-a(19) from _Vaclav Kotesovec_, May 28 2011