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 A240458 #6 Jun 02 2025 09:58:36 %S A240458 16,375,7589,143237,2632690,47636104,854671234,15259447330, %T A240458 271656519692,4827854253348,85712180553955,1520764060039331, %U A240458 26972330503325401,478273812124771069,8479592950284098842,150327053689019608051 %N A240458 Number of nX4 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4. %C A240458 Column 4 of A240460 %H A240458 R. H. Hardin, <a href="/A240458/b240458.txt">Table of n, a(n) for n = 1..210</a> %e A240458 Some solutions for n=4 %e A240458 ..2..0..0..0....0..2..2..2....0..0..2..0....0..2..2..0....2..2..2..0 %e A240458 ..2..0..0..2....2..2..2..0....2..2..2..2....2..0..2..0....0..2..0..2 %e A240458 ..2..2..0..0....2..1..1..0....2..2..0..0....2..2..0..2....2..0..0..2 %e A240458 ..0..2..0..2....2..1..3..2....2..0..0..2....2..0..2..0....0..2..2..0 %K A240458 nonn %O A240458 1,1 %A A240458 _R. H. Hardin_, Apr 05 2014