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 A241261 #5 Jan 15 2024 19:34:35 %S A241261 20,488,2111,13328,225191,1558957,13138271,205823368,1596727720, %T A241261 16865140873 %N A241261 Number of 7 X n 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4. %C A241261 Row 7 of A241255. %e A241261 Some solutions for n=3 %e A241261 ..3..3..2....3..3..2....2..2..3....3..3..2....3..3..2....3..3..2....3..3..2 %e A241261 ..2..1..1....2..1..1....0..0..2....2..1..1....2..1..3....2..1..3....2..1..3 %e A241261 ..2..2..2....2..2..2....0..0..2....0..2..2....2..1..3....2..2..3....2..1..3 %e A241261 ..2..1..3....0..0..2....3..3..2....0..3..3....2..2..3....0..0..3....2..0..1 %e A241261 ..2..1..1....0..0..2....0..3..3....2..2..3....2..2..2....2..0..2....0..0..2 %e A241261 ..2..2..2....0..3..3....0..2..1....2..1..1....2..0..2....0..0..2....0..3..1 %e A241261 ..2..0..2....2..2..3....3..3..2....3..2..1....0..0..2....0..0..2....3..2..3 %Y A241261 Cf. A241255. %K A241261 nonn %O A241261 1,1 %A A241261 _R. H. Hardin_, Apr 18 2014