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 A284336 #6 Apr 05 2020 22:55:28 %S A284336 4,13,49,373,2259,18114,120058,959041,6725380,53524100,389145239, %T A284336 3078502323,22909373317,180462930528,1364622501692,10722180215723, %U A284336 81993405397067,643447267719348,4960055945696896,38910411283028492 %N A284336 Number of 3 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 A284336 Row 3 of A284334. %H A284336 R. H. Hardin, <a href="/A284336/b284336.txt">Table of n, a(n) for n = 1..210</a> %e A284336 Some solutions for n=4 %e A284336 ..0..1..1..1. .0..0..0..0. .0..0..0..1. .0..1..1..0. .0..0..1..1 %e A284336 ..1..1..0..0. .0..0..0..0. .0..1..1..1. .0..1..0..1. .1..1..0..0 %e A284336 ..0..0..1..0. .0..0..0..0. .1..0..0..1. .1..0..1..0. .1..1..0..0 %Y A284336 Cf. A284334. %K A284336 nonn %O A284336 1,1 %A A284336 _R. H. Hardin_, Mar 25 2017