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 A093991 #9 Jan 13 2023 09:17:55 %S A093991 1,0,4,2,30,24,280,278,2841,3256,30324,38830,334540 %N A093991 Number of n-celled polyzebras with bilateral symmetry. %C A093991 A polyzebra is a (2,3) leaper. A polyzebra need not be connected in the usual edge-connected sense. %Y A093991 Cf. A093877, A093989, A093990, A093992, A030444. %K A093991 nonn,more %O A093991 1,3 %A A093991 _Joseph Myers_, May 25 2004 %E A093991 a(12)-a(13) from _John Mason_, Jan 13 2023