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 A293103 #6 Apr 06 2020 00:07:17 %S A293103 0,30,554,8088,114318,1676740,24773296,370085158,5573917456, %T A293103 84505086146,1288142241806,19723300256104,303110117057606, %U A293103 4672886017374940,72233860901133456,1119204087096130496,17376470515536487116 %N A293103 Number of 4 X n 0..1 arrays with the number of 1's horizontally, diagonally or antidiagonally adjacent to some 0 two less than the number of 0's adjacent to some 1. %C A293103 Row 4 of A293100. %H A293103 R. H. Hardin, <a href="/A293103/b293103.txt">Table of n, a(n) for n = 1..134</a> %e A293103 Some solutions for n=4 %e A293103 ..1..0..0..1. .1..1..1..0. .1..1..1..0. .0..0..0..0. .0..1..0..0 %e A293103 ..1..1..0..1. .1..0..0..0. .0..1..1..0. .0..1..0..1. .1..1..0..0 %e A293103 ..0..0..0..0. .0..0..0..1. .0..0..0..1. .1..1..0..0. .0..1..0..1 %e A293103 ..1..0..1..0. .0..0..0..0. .0..0..0..0. .0..1..0..1. .0..1..0..0 %Y A293103 Cf. A293100. %K A293103 nonn %O A293103 1,2 %A A293103 _R. H. Hardin_, Sep 30 2017