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 A267972 #4 Jan 23 2016 10:00:34 %S A267972 250,62500,12067722,2208460532,370962601314,58977586280183, %T A267972 8920181825287255,1295459314730053526,181620283990314798496, %U A267972 24698703052360112375559,3269943855458863743367027 %N A267972 Number of nX4 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 A267972 Column 4 of A267974. %H A267972 R. H. Hardin, <a href="/A267972/b267972.txt">Table of n, a(n) for n = 1..42</a> %e A267972 Some solutions for n=2 %e A267972 ..0..1..0..3....0..1..0..0....3..2..1..1....2..0..3..0....0..3..2..0 %e A267972 ..3..1..3..0....0..3..1..2....2..3..2..2....0..3..2..1....1..2..2..0 %Y A267972 Cf. A267974. %K A267972 nonn %O A267972 1,1 %A A267972 _R. H. Hardin_, Jan 23 2016