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 A293088 #6 Apr 05 2020 23:41:03 %S A293088 0,0,5,23,124,518,2103,8304,32561,127188,497290,1944992,7609668, %T A293088 29781058,116601073,456769568,1790429581,7022484654,27560850105, %U A293088 108231066278,425262686638,1671850997415,6576007463557,25878627324698,101888312587090 %N A293088 Number of 2 X n 0..1 arrays with the number of 1's horizontally or antidiagonally adjacent to some 0 two less than the number of 0's adjacent to some 1. %C A293088 Row 2 of A293087. %H A293088 R. H. Hardin, <a href="/A293088/b293088.txt">Table of n, a(n) for n = 1..210</a> %e A293088 Some solutions for n=4 %e A293088 ..0..1..0..0. .1..0..0..0. .1..1..0..0. .1..0..0..0. .0..0..1..0 %e A293088 ..0..0..0..1. .0..0..1..0. .0..0..1..1. .0..1..0..0. .0..0..1..0 %Y A293088 Cf. A293087. %K A293088 nonn %O A293088 1,3 %A A293088 _R. H. Hardin_, Sep 30 2017