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 A197197 #7 Jun 02 2025 04:46:08 %S A197197 9,85,621,5311,42664,350711,2873141,23497244,192348965,1574634137, %T A197197 12888915436,105499317727,863568784956,7068699587730,57860690577672, %U A197197 473616132534126,3876768069957732,31733162865254064,259750677790161795 %N A197197 Number of nX6 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 4,1,3,2,0 for x=0,1,2,3,4. %C A197197 Every 0 is next to 0 4's, every 1 is next to 1 1's, every 2 is next to 2 3's, every 3 is next to 3 2's, every 4 is next to 4 0's %C A197197 Column 6 of A197199 %H A197197 R. H. Hardin, <a href="/A197197/b197197.txt">Table of n, a(n) for n = 1..210</a> %e A197197 Some solutions for n=4 %e A197197 ..0..0..0..1..1..0....0..1..1..0..0..0....1..0..0..0..1..1....0..0..0..1..1..0 %e A197197 ..0..0..1..0..0..1....0..0..0..0..0..0....1..0..0..0..0..0....0..1..1..0..0..1 %e A197197 ..0..0..1..0..0..1....0..0..0..1..1..0....0..0..1..1..0..0....0..0..0..0..0..1 %e A197197 ..0..0..0..0..0..0....0..1..1..0..0..0....0..0..0..0..1..1....0..0..1..1..0..0 %K A197197 nonn %O A197197 1,1 %A A197197 _R. H. Hardin_ Oct 11 2011