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 A265242 #6 Aug 12 2016 06:53:58 %S A265242 1,10,92,888,8880,91180,955320,10168092,109595168,1193414004, %T A265242 13106207640,144965453160,1613228920704,18047090084256, %U A265242 202816635014976,2288462757997500,25913609592575040,294366270662992612 %N A265242 Number of 3Xn arrays containing n copies of 0..3-1 with no equal antidiagonal neighbors and new values introduced sequentially from 0. %C A265242 Row 3 of A265241. %H A265242 R. H. Hardin, <a href="/A265242/b265242.txt">Table of n, a(n) for n = 1..109</a> %e A265242 Some solutions for n=4 %e A265242 ..0..0..0..0....0..0..1..0....0..1..1..1....0..1..0..2....0..0..1..1 %e A265242 ..1..1..2..2....2..2..1..2....2..0..2..0....0..1..1..1....2..2..0..1 %e A265242 ..2..1..1..2....1..2..1..0....2..0..2..1....2..2..0..2....0..1..2..2 %Y A265242 Cf. A265241. %K A265242 nonn %O A265242 1,2 %A A265242 _R. H. Hardin_, Dec 06 2015