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 A194774 #7 Jul 22 2025 12:35:59 %S A194774 268,672,1736,4464,11686,30608,80961,214469,570921,1521287,4061881, %T A194774 10847647,28982750,77406210,206655490,551301206,1469565060,3913609398, %U A194774 10412354243,27674510615,73480819187,194908131709,516485443463 %N A194774 Number of lower triangles of an (n+6)X(n+6) 0..4 array with new values introduced in row major order 0..4 and no element unequal to more than one horizontal or vertical neighbor. %C A194774 Column 4 of A194778 %H A194774 R. H. Hardin, <a href="/A194774/b194774.txt">Table of n, a(n) for n = 1..24</a> %e A194774 All solutions for 7X7 including a 4 %e A194774 ..0..............0..............0 %e A194774 ..1.1............1.1............1.1 %e A194774 ..1.1.2..........1.1.1..........1.1.1 %e A194774 ..1.1.2.2........2.2.2.2........2.2.2.2 %e A194774 ..1.1.2.2.3......2.2.2.2.2......2.2.2.2.3 %e A194774 ..1.1.2.2.3.3....3.3.3.3.3.3....2.2.2.2.3.3 %e A194774 ..1.1.2.2.3.3.4..3.3.3.3.3.3.4..2.2.2.2.3.3.4 %K A194774 nonn %O A194774 1,1 %A A194774 _R. H. Hardin_ Sep 02 2011