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 A277770 #4 Oct 29 2016 07:33:30 %S A277770 0,56,3666,270291,20049229,1487830718,110036582827,8144355400488, %T A277770 602835463794197,44616311792079721,3302197502743906336, %U A277770 244405001824291326112,18089091210686721809130,1338824653239265489456655 %N A277770 Number of 5Xn 0..2 arrays with every element equal to some element at offset (-1,-1) (-1,0) (-1,1) (0,-1) (0,1) or (1,0) both plus 1 mod 3 and minus 1 mod 3, with new values introduced in order 0..2. %C A277770 Row 5 of A277767. %H A277770 R. H. Hardin, <a href="/A277770/b277770.txt">Table of n, a(n) for n = 1..210</a> %e A277770 Some solutions for n=3 %e A277770 ..0..1..2. .0..1..2. .0..1..2. .0..1..2. .0..1..2. .0..1..2. .0..1..0 %e A277770 ..2..2..0. .2..1..0. .2..2..0. .2..1..0. .2..0..0. .2..0..0. .2..2..2 %e A277770 ..1..0..1. .2..1..1. .0..1..2. .0..2..0. .2..1..2. .1..1..0. .1..0..1 %e A277770 ..1..2..1. .0..1..2. .0..2..1. .2..2..1. .0..1..0. .0..0..2. .2..0..2 %e A277770 ..0..0..1. .1..2..0. .2..1..0. .1..0..2. .0..2..2. .2..1..0. .1..1..2 %Y A277770 Cf. A277767. %K A277770 nonn %O A277770 1,2 %A A277770 _R. H. Hardin_, Oct 29 2016