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 A093990 #9 Jan 13 2023 09:17:51 %S A093990 1,2,8,68,550,5404,54768,581868,6329407,70335294,794064734,9083306888, %T A093990 105021662154 %N A093990 Number of one-sided n-celled polyzebras (or zebra-move-connected polyominoes). %C A093990 A polyzebra is a (2,3) leaper. A polyzebra need not be connected in the usual edge-connected sense. %Y A093990 Cf. A093877, A093989, A093991, A093992, A030444. %K A093990 nonn,more %O A093990 1,2 %A A093990 _Joseph Myers_, May 25 2004 %E A093990 a(12)-a(13) from _John Mason_, Jan 13 2023