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 A030445 #13 Jan 13 2023 06:32:35 %S A030445 1,2,8,68,550,5328,52484,534793,5513338,57494308,604212943,6392547793, %T A030445 68014392915 %N A030445 Number of one-sided n-celled polyknights. %C A030445 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. %e A030445 The 2 polyknights with 2 cells: %e A030445 X.. ..X %e A030445 ..X X.. %e A030445 The 8 polyknights with 3 cells: %e A030445 X. X.. X.. X... X.X .X. .X. X... %e A030445 .. ... ..X .... ... X.. ..X ...X %e A030445 .X .X. ... .X.. .X. ..X X.. .X.. %e A030445 .. ... .X. ...X %e A030445 X. ..X %Y A030445 Cf. A030444, A030446, A030447, A030448. %K A030445 nonn,nice,more %O A030445 1,2 %A A030445 _David W. Wilson_ %E A030445 Corrected and extended by _Joseph Myers_, May 21 2004 %E A030445 a(12)-a(13) from _John Mason_, Jan 13 2023