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 A240289 #6 Nov 17 2022 18:00:11 %S A240289 10,251,5443,218658,5646644,281488213,8597299482,500877279597, %T A240289 17050417858056,1080907153540112,38722390548732389, %U A240289 2543690845510555315,92980052380043106702,6189999145510145997607,227935320097083755541303 %N A240289 Number of 6 X n 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4. %C A240289 Row 6 of A240284. %H A240289 R. H. Hardin, <a href="/A240289/b240289.txt">Table of n, a(n) for n = 1..54</a> %e A240289 Some solutions for n=3 %e A240289 ..3..1..3....3..1..3....3..1..3....3..1..3....3..1..3....3..1..3....3..1..3 %e A240289 ..3..1..3....3..1..2....3..1..3....3..2..3....3..1..3....2..0..2....2..0..0 %e A240289 ..3..1..3....2..1..1....2..1..3....3..2..3....3..2..3....2..1..1....2..1..2 %e A240289 ..2..2..2....3..3..1....3..3..2....2..0..0....2..1..2....3..3..1....3..1..2 %e A240289 ..2..1..3....3..1..2....2..2..0....3..1..2....3..1..2....2..1..3....3..2..0 %e A240289 ..2..1..1....2..2..2....2..1..3....2..2..2....3..2..1....3..1..2....2..1..3 %Y A240289 Cf. A240284. %K A240289 nonn %O A240289 1,1 %A A240289 _R. H. Hardin_, Apr 03 2014