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 A239824 #6 Jun 02 2025 09:33:30 %S A239824 129,15266,2405330,366379173,54668820459,8243207656791, %T A239824 1246285848518417,188159790209407764,28411744326144591606, %U A239824 4291882371849878160532,648352047493507989834712,97941932841918812449706827 %N A239824 Number of 6Xn 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of the elements above it, modulo 4. %C A239824 Row 6 of A239819 %H A239824 R. H. Hardin, <a href="/A239824/b239824.txt">Table of n, a(n) for n = 1..210</a> %e A239824 Some solutions for n=2 %e A239824 ..2..3....2..3....3..2....2..3....2..0....2..3....3..0....3..0....2..0....2..0 %e A239824 ..1..3....1..2....1..0....2..3....1..0....2..3....2..3....2..0....1..0....1..2 %e A239824 ..1..0....2..1....3..1....2..0....1..0....3..2....1..2....1..2....3..0....3..1 %e A239824 ..3..2....1..2....1..3....1..2....3..0....3..2....1..3....1..0....2..3....1..3 %e A239824 ..3..2....1..0....3..1....1..0....3..0....2..1....1..2....2..0....3..2....3..1 %e A239824 ..1..2....3..0....3..1....3..2....1..2....2..3....3..2....3..1....3..0....2..3 %K A239824 nonn %O A239824 1,1 %A A239824 _R. H. Hardin_, Mar 27 2014