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 A285155 #6 Apr 05 2020 23:15:09 %S A285155 0,56,786,11574,159060,2284666,33371602,495256266,7426444716, %T A285155 112236717358,1706444466326,26070175620594,399870502837122, %U A285155 6153779131538066,94972379110894900,1469319459956729810 %N A285155 Number of 4 X n 0..1 arrays with the number of 1's horizontally or antidiagonally adjacent to some 0 one less than the number of 0's adjacent to some 1. %C A285155 Row 4 of A285152. %H A285155 R. H. Hardin, <a href="/A285155/b285155.txt">Table of n, a(n) for n = 1..176</a> %e A285155 Some solutions for n=4 %e A285155 ..1..0..0..1. .0..0..1..0. .0..0..1..0. .1..1..0..1. .0..0..1..1 %e A285155 ..0..1..0..1. .0..1..0..1. .0..0..0..0. .0..0..1..0. .0..0..1..1 %e A285155 ..0..1..1..1. .0..1..0..0. .1..0..1..1. .0..0..1..1. .0..0..1..0 %e A285155 ..0..0..0..0. .1..1..0..1. .1..0..0..1. .0..0..1..1. .0..0..1..1 %Y A285155 Cf. A285152. %K A285155 nonn %O A285155 1,2 %A A285155 _R. H. Hardin_, Apr 12 2017