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 A208300 #7 May 18 2020 19:56:29 %S A208300 1,52,373780,33093356640,14216420563705724,19558496206477343793824, %T A208300 67939294184937980415465539016,510275358863420934339418249390485008, %U A208300 7427072102775408021555037479377677353344288,193059270325130351714478780835691676245238854091968 %N A208300 Number of n X 6 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors). %H A208300 Andrew Howroyd, <a href="/A208300/b208300.txt">Table of n, a(n) for n = 0..50</a> %e A208300 Some solutions for n=4: %e A208300 ..0..1..0..1..0..1....0..1..0..1..2..1....0..1..0..1..0..1....0..1..0..1..2..1 %e A208300 ..0..1..0..1..0..1....0..1..0..1..0..1....0..1..0..1..0..1....0..1..0..3..0..1 %e A208300 ..2..1..3..1..0..1....2..1..2..1..0..1....0..1..0..1..0..1....0..1..0..2..3..0 %e A208300 ..0..1..0..1..2..0....2..0..2..3..0..1....0..1..0..1..0..1....0..1..0..1..2..0 %Y A208300 Column 6 of A208301. %K A208300 nonn %O A208300 0,2 %A A208300 _R. H. Hardin_, Feb 25 2012 %E A208300 a(0)=1 prepended and terms a(6) and beyond from _Andrew Howroyd_, May 18 2020