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 A197448 #7 Jun 02 2025 04:55:28 %S A197448 11,321,15410,585194,23829080,982926107,40087361395,1640477445822, %T A197448 67160665746869,2747685400705119,112433629005651948, %U A197448 4600917175526994358,188267595598497672073,7703877269427034462338,315242428170240015474340 %N A197448 Number of nX6 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,1,1,0,0 for x=0,1,2,3,4. %C A197448 Every 0 is next to 0 2's, every 1 is next to 1 1's, every 2 is next to 2 1's, every 3 is next to 3 0's, every 4 is next to 4 0's %C A197448 Column 6 of A197450 %H A197448 R. H. Hardin, <a href="/A197448/b197448.txt">Table of n, a(n) for n = 1..210</a> %e A197448 Some solutions containing all values 0 to 4 for n=4 %e A197448 ..1..1..0..0..3..0....2..1..1..0..1..1....0..0..0..1..2..1....0..0..0..0..1..1 %e A197448 ..2..2..3..0..0..3....1..0..0..0..0..0....0..0..0..1..2..1....1..3..0..4..0..0 %e A197448 ..1..1..0..0..4..0....1..0..4..0..0..0....0..0..4..0..3..0....1..0..0..0..0..3 %e A197448 ..0..0..3..0..0..0....0..3..0..0..3..0....0..0..0..3..0..0....2..1..1..0..0..0 %K A197448 nonn %O A197448 1,1 %A A197448 _R. H. Hardin_ Oct 15 2011