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 A268772 #4 Feb 13 2016 08:26:47 %S A268772 240,620,5214,46312,387146,3104544,24222418,185142872,1393319226, %T A268772 10357051740,76224579034,556383657268,4033179662378,29064236056520, %U A268772 208382539816438,1487439977791192,10576114792480666,74940142727337224 %N A268772 Number of nX6 0..2 arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once. %C A268772 Column 6 of A268774. %H A268772 R. H. Hardin, <a href="/A268772/b268772.txt">Table of n, a(n) for n = 1..210</a> %F A268772 Empirical: a(n) = 6*a(n-1) +51*a(n-2) -214*a(n-3) -1074*a(n-4) +2018*a(n-5) +7713*a(n-6) -10572*a(n-7) -22926*a(n-8) +30116*a(n-9) +25283*a(n-10) -32400*a(n-11) -15148*a(n-12) +15184*a(n-13) +5660*a(n-14) -2688*a(n-15) -1024*a(n-16) for n>18 %e A268772 Some solutions for n=4 %e A268772 ..1..0..0..1..1..0. .2..2..2..1..2..1. .0..0..0..1..0..0. .1..2..2..2..2..1 %e A268772 ..0..0..0..0..0..0. .2..2..2..2..2..2. .1..1..0..0..0..0. .2..1..2..2..2..2 %e A268772 ..0..0..0..0..0..1. .1..2..2..1..2..1. .0..0..0..0..0..0. .2..2..2..2..2..2 %e A268772 ..0..0..1..0..0..0. .2..2..2..2..2..1. .1..0..0..1..0..0. .1..2..1..2..2..2 %Y A268772 Cf. A268774. %K A268772 nonn %O A268772 1,1 %A A268772 _R. H. Hardin_, Feb 13 2016