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 A277772 #3 Oct 29 2016 07:34:46 %S A277772 0,1304,560809,280603511,145416104585,74591651561541, %T A277772 38224184451654485,19594056304528558357,10045114847567207328081, %U A277772 5149301096028551482379853,2639661525564889493885834000,1353158899116458615963424246675 %N A277772 Number of 7Xn 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 A277772 Row 7 of A277767. %e A277772 Some solutions for n=2 %e A277772 ..0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1 %e A277772 ..2..2. .2..2. .2..2. .2..2. .2..2. .2..2. .2..2. .2..2. .2..2. .2..2 %e A277772 ..0..2. .0..1. .1..0. .1..0. .1..0. .0..1. .1..0. .0..1. .1..0. .0..2 %e A277772 ..1..1. .2..0. .0..2. .0..1. .2..0. .1..0. .2..1. .0..2. .2..2. .1..1 %e A277772 ..2..0. .1..0. .1..1. .2..2. .1..0. .2..2. .0..1. .1..2. .1..0. .0..2 %e A277772 ..1..2. .0..2. .2..0. .1..0. .2..0. .0..1. .1..2. .0..2. .1..2. .0..1 %e A277772 ..1..0. .1..0. .1..0. .0..2. .2..1. .2..1. .0..0. .1..0. .0..0. .0..2 %Y A277772 Cf. A277767. %K A277772 nonn %O A277772 1,2 %A A277772 _R. H. Hardin_, Oct 29 2016