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 A269292 #4 Feb 21 2016 09:29:40 %S A269292 256,29160,1698732,87559668,4204943820,193446959076,8642330207532, %T A269292 377958654569412,16263720330382476,690974658284107428, %U A269292 29056221832723692012,1211537520551702429316,50159175757694154381132 %N A269292 Number of 4Xn 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three no more than once. %C A269292 Row 4 of A269289. %H A269292 R. H. Hardin, <a href="/A269292/b269292.txt">Table of n, a(n) for n = 1..210</a> %F A269292 Empirical: a(n) = 96*a(n-1) -3108*a(n-2) +40720*a(n-3) -265326*a(n-4) +931200*a(n-5) -1766452*a(n-6) +1678992*a(n-7) -622521*a(n-8) for n>12 %e A269292 Some solutions for n=2 %e A269292 ..1..1. .2..2. .0..2. .0..1. .0..0. .1..0. .2..2. .0..1. .3..1. .1..1 %e A269292 ..3..1. .3..0. .0..2. .0..2. .3..2. .1..1. .3..2. .0..1. .3..0. .1..3 %e A269292 ..0..0. .1..3. .2..0. .3..0. .2..0. .0..3. .3..0. .3..2. .2..3. .2..3 %e A269292 ..3..3. .1..3. .3..2. .2..0. .1..1. .3..3. .1..0. .0..0. .2..0. .1..2 %Y A269292 Cf. A269289. %K A269292 nonn %O A269292 1,1 %A A269292 _R. H. Hardin_, Feb 21 2016