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 A268027 #4 Jan 24 2016 14:11:22 %S A268027 24,576,13824,295962,6042732,117582228,2205234900,40088968398, %T A268027 709841497188,12287419441812,208546228493724,3478737714576768, %U A268027 57143989099923852,925889151644801202,14817867358400405148 %N A268027 Number of 3Xn 0..2 arrays with every repeated value in every row greater than or equal to, and in every column greater than, the previous repeated value. %C A268027 Row 3 of A268026. %H A268027 R. H. Hardin, <a href="/A268027/b268027.txt">Table of n, a(n) for n = 1..210</a> %H A268027 R. H. Hardin, <a href="/A268027/a268027.txt">Empirical recurrence of order 86</a> %F A268027 Empirical recurrence of order 86 (see link above) %e A268027 Some solutions for n=3 %e A268027 ..1..2..1....1..2..0....0..0..2....1..1..2....2..0..0....2..1..1....0..2..2 %e A268027 ..0..2..1....0..1..1....1..1..0....1..2..0....1..2..0....1..0..2....2..1..2 %e A268027 ..2..0..2....2..2..1....1..1..2....0..0..1....1..1..1....1..0..1....2..1..1 %Y A268027 Cf. A268026. %K A268027 nonn %O A268027 1,1 %A A268027 _R. H. Hardin_, Jan 24 2016