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 A267977 #4 Jan 23 2016 10:04:08 %S A267977 60,3600,216000,12067722,648144348,33600202086,1691726672094, %T A267977 83078866656672,3993019853352132,188338933978296900, %U A267977 8737015871231173194,399355062781386269430,18013039522804400997948,802791844156171633174662 %N A267977 Number of 3Xn 0..3 arrays with every repeated value in every row greater than or equal to, and in every column greater than, the previous repeated value. %C A267977 Row 3 of A267974. %H A267977 R. H. Hardin, <a href="/A267977/b267977.txt">Table of n, a(n) for n = 1..210</a> %e A267977 Some solutions for n=2 %e A267977 ..1..0....1..2....0..3....1..1....3..2....1..0....3..0....3..2....2..0....3..1 %e A267977 ..0..2....2..2....1..1....3..2....3..2....3..3....1..3....2..2....0..1....3..0 %e A267977 ..3..2....1..0....3..3....0..2....1..3....0..0....0..0....3..3....0..3....2..3 %Y A267977 Cf. A267974. %K A267977 nonn %O A267977 1,1 %A A267977 _R. H. Hardin_, Jan 23 2016