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 A240463 #6 Jun 02 2025 09:59:04 %S A240463 28,476,8187,143237,2501883,43654661,761700369,13290291978, %T A240463 231879123545,4045526615228,70580191049583,1231367510496942, %U A240463 21482798448261309,374794402280678279,6538751854554181415,114076545131533814184 %N A240463 Number of 4Xn 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4. %C A240463 Row 4 of A240460 %H A240463 R. H. Hardin, <a href="/A240463/b240463.txt">Table of n, a(n) for n = 1..210</a> %e A240463 Some solutions for n=4 %e A240463 ..2..2..0..2....0..0..2..0....0..0..0..2....0..2..2..2....0..0..2..2 %e A240463 ..0..2..2..2....2..2..2..2....2..0..0..0....2..2..0..0....0..0..0..2 %e A240463 ..0..2..2..2....2..0..2..2....3..1..0..3....0..2..0..0....0..0..3..2 %e A240463 ..0..2..2..0....0..0..2..2....3..3..2..2....3..3..0..0....0..0..2..2 %K A240463 nonn %O A240463 1,1 %A A240463 _R. H. Hardin_, Apr 05 2014