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 A240404 #6 Jun 02 2025 09:55:00 %S A240404 7,77,1381,13648,257243,3366314,43820839,766539340,9754760605, %T A240404 139442821024,2170660872648,28425049610123,428335838522441, %U A240404 6234809732594859,85273887883266129,1280632016847475497 %N A240404 Number of nX5 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 zero plus the sum of the elements diagonally to its northwest, modulo 4. %C A240404 Column 5 of A240406 %H A240404 R. H. Hardin, <a href="/A240404/b240404.txt">Table of n, a(n) for n = 1..210</a> %e A240404 Some solutions for n=4 %e A240404 ..2..1..1..2..1....2..1..2..1..1....2..1..2..1..1....2..1..1..2..1 %e A240404 ..3..1..2..2..3....3..1..3..3..2....3..1..2..1..2....2..1..3..0..1 %e A240404 ..3..2..0..0..0....3..2..1..1..3....3..2..0..0..1....2..0..2..3..3 %e A240404 ..2..0..0..0..1....2..0..2..2..2....2..0..0..0..0....2..0..0..2..2 %K A240404 nonn %O A240404 1,1 %A A240404 _R. H. Hardin_, Apr 04 2014