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 A293096 #6 Apr 05 2020 23:46:11 %S A293096 0,42,567,8088,115870,1710994,25504769,383909610,5821195059, %T A293096 88774881168,1360012227225,20913114635864,322580968736023, %U A293096 4988786216140076,77325995176393118,1200887079044838246,18681923365562958635 %N A293096 Number of n X 4 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 A293096 Column 4 of A293100. %H A293096 R. H. Hardin, <a href="/A293096/b293096.txt">Table of n, a(n) for n = 1..162</a> %e A293096 Some solutions for n=4 %e A293096 ..0..1..1..1. .0..0..0..1. .0..0..0..1. .0..1..0..0. .0..0..0..0 %e A293096 ..0..0..0..1. .0..0..1..1. .0..1..1..0. .0..1..1..0. .1..1..1..0 %e A293096 ..0..0..1..0. .0..0..0..0. .0..1..0..1. .0..1..0..1. .1..0..1..0 %e A293096 ..0..1..0..1. .1..1..1..0. .1..0..0..1. .1..0..1..0. .1..0..1..0 %Y A293096 Cf. A293100. %K A293096 nonn %O A293096 1,2 %A A293096 _R. H. Hardin_, Sep 30 2017