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 A030447 #12 Jan 13 2023 06:32:15 %S A030447 1,0,4,2,30,32,274,403,2694,4604,27365,50777,282343 %N A030447 Number of n-celled polyknights with bilateral symmetry. %C A030447 A polyknight is a variant of a polyomino in which two tiles a knight's move apart are considered adjacent. A polyknight need not be connected in the sense of a polyomino. %Y A030447 Cf. A030445, A030444, A030446, A030448. %K A030447 nonn,more %O A030447 1,3 %A A030447 _David W. Wilson_ %E A030447 Corrected and extended by _Joseph Myers_, May 21 2004 %E A030447 a(12)-a(13) from _John Mason_, Jan 13 2023