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 A269009 #4 Feb 17 2016 12:03:19 %S A269009 20,272,4948,73568,1049588,14382480,192100836,2516546784,32481770852, %T A269009 414339126768,5234937372516,65617049910368,816985376286500, %U A269009 10114119489148976,124593533629907540,1528232910934667360 %N A269009 Number of nX6 binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two exactly once. %C A269009 Column 6 of A269011. %H A269009 R. H. Hardin, <a href="/A269009/b269009.txt">Table of n, a(n) for n = 1..210</a> %F A269009 Empirical: a(n) = 28*a(n-1) -230*a(n-2) +192*a(n-3) +3805*a(n-4) -5776*a(n-5) -27808*a(n-6) +25744*a(n-7) +101333*a(n-8) -13916*a(n-9) -149690*a(n-10) -66848*a(n-11) +23183*a(n-12) +9888*a(n-13) -2304*a(n-14) %e A269009 Some solutions for n=4 %e A269009 ..0..0..1..0..0..0. .0..1..0..1..0..1. .1..0..0..1..1..0. .0..0..0..1..0..0 %e A269009 ..0..0..1..0..0..1. .0..0..0..0..0..1. .0..0..0..0..0..0. .0..0..1..0..0..0 %e A269009 ..0..0..1..0..0..0. .1..0..1..0..1..0. .0..0..1..0..0..0. .0..0..0..0..0..1 %e A269009 ..0..0..0..1..0..0. .1..0..1..0..0..0. .0..0..0..0..0..0. .1..0..1..0..0..0 %Y A269009 Cf. A269011. %K A269009 nonn %O A269009 1,1 %A A269009 _R. H. Hardin_, Feb 17 2016