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 A284337 #6 Apr 05 2020 22:56:14 %S A284337 8,42,415,5130,68458,966889,13941789,204883324,3047634270,45762072338, %T A284337 692220227870,10532157295267,161005503857341,2470999756894057, %U A284337 38049394554096755,587563040419449964,9095438545580032870 %N A284337 Number of 4 X n 0..1 arrays with the number of 1's horizontally, diagonally or antidiagonally adjacent to some 0 equal to the number of 0's adjacent to some 1, with top left element zero. %C A284337 Row 4 of A284334. %H A284337 R. H. Hardin, <a href="/A284337/b284337.txt">Table of n, a(n) for n = 1..128</a> %e A284337 Some solutions for n=4 %e A284337 ..0..1..1..0. .0..0..0..1. .0..0..1..0. .0..0..0..0. .0..0..1..0 %e A284337 ..1..1..1..0. .1..0..0..1. .1..1..1..1. .1..0..1..0. .0..1..0..1 %e A284337 ..1..0..0..1. .0..0..1..1. .0..1..0..1. .1..1..1..1. .1..0..1..1 %e A284337 ..0..0..0..0. .0..0..1..1. .0..0..1..0. .1..0..1..0. .1..0..1..0 %Y A284337 Cf. A284334. %K A284337 nonn %O A284337 1,1 %A A284337 _R. H. Hardin_, Mar 25 2017