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 A194619 #9 Jun 04 2025 00:30:36 %S A194619 29241,205801866,214726600125,38969955227338,2481372954501732, %T A194619 77572756670578163,1525002446582690839,20406859321612678912, %U A194619 206774026729010778294,1658596651668908616516,11050418508749912011440 %N A194619 Half the number of lower triangles of a 6 X 6 0..n array with no element equal to the average of its horizontal and vertical neighbors. %e A194619 Some solutions for n=2 %e A194619 ..0............0............0............0............0............0 %e A194619 ..1.0..........1.0..........1.0..........1.0..........1.0..........1.0 %e A194619 ..0.0.2........0.0.1........0.0.1........0.0.1........0.0.1........0.0.1 %e A194619 ..0.0.0.0......0.0.0.2......0.0.1.0......0.0.0.0......0.0.1.2......0.0.0.2 %e A194619 ..1.1.0.1.0....1.1.2.0.0....1.0.0.1.0....2.2.0.1.0....2.1.0.2.2....1.2.0.2.1 %e A194619 ..1.0.1.0.0.2..1.0.0.2.2.1..2.1.2.2.0.1..0.0.0.1.1.0..0.1.0.1.0.2..2.2.0.2.1.2 %Y A194619 Row 5 of A194615. %K A194619 nonn %O A194619 1,1 %A A194619 _R. H. Hardin_, Aug 30 2011