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 A208299 #10 May 18 2020 19:56:23 %S A208299 1,15,12840,87852626,2227156082842,148049849095504726, %T A208299 21183598567292002167082,5737167377815628378510929822, %U A208299 2685975192008614716088213333413834,2031667423243870021802621888823332638846,2356075680798443401764258655433216618467066594 %N A208299 Number of n X 5 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 A208299 Andrew Howroyd, <a href="/A208299/b208299.txt">Table of n, a(n) for n = 0..100</a> %e A208299 Some solutions for n=4: %e A208299 ..0..1..0..1..0....0..1..0..1..0....0..1..2..0..3....0..1..0..1..0 %e A208299 ..2..1..0..1..2....2..1..0..1..0....0..1..2..4..0....0..1..0..1..0 %e A208299 ..0..1..0..1..0....0..1..0..2..0....0..1..0..1..0....0..1..0..1..0 %e A208299 ..0..1..0..1..0....0..1..0..2..0....0..1..0..1..4....0..1..2..1..0 %Y A208299 Column 5 of A208301. %K A208299 nonn %O A208299 0,2 %A A208299 _R. H. Hardin_, Feb 25 2012 %E A208299 a(0)=1 prepended and terms a(10) and beyond from _Andrew Howroyd_, May 18 2020