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 A200799 #7 Mar 27 2023 15:36:49 %S A200799 187,622645,2060918000,6852264918471,22781978610167987, %T A200799 75743730886453371522,251826890612151285556718, %U A200799 837254535307721417534184492,2783639010978210077196779661724 %N A200799 Number of n X 6 0..3 arrays with values 0..3 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors. %C A200799 Column 6 of A200801. %H A200799 R. H. Hardin, <a href="/A200799/b200799.txt">Table of n, a(n) for n = 1..28</a> %e A200799 Some solutions for n=3 %e A200799 ..0..1..0..0..2..1....0..1..0..2..2..2....0..1..0..0..0..0....0..1..0..1..2..3 %e A200799 ..1..0..0..1..2..2....1..0..0..3..1..3....1..0..0..2..1..0....1..0..0..2..3..3 %e A200799 ..0..0..1..2..3..2....0..0..1..2..0..2....0..0..1..2..2..2....0..0..1..0..1..2 %Y A200799 Cf. A200801. %K A200799 nonn %O A200799 1,1 %A A200799 _R. H. Hardin_, Nov 22 2011