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 A197249 #7 Jun 02 2025 04:48:54 %S A197249 2,192,1035,16773,213912,3264225,48703999,692974749,9613268927, %T A197249 144634486646,2038308764828,29317910548935,416838295672468, %U A197249 6110472912181664,87970427980764925,1247341042216025997 %N A197249 Number of nX7 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 0,0,1,1,1 for x=0,1,2,3,4. %C A197249 Every 0 is next to 0 0's, every 1 is next to 1 0's, every 2 is next to 2 1's, every 3 is next to 3 1's, every 4 is next to 4 1's %C A197249 Column 7 of A197250 %H A197249 R. H. Hardin, <a href="/A197249/b197249.txt">Table of n, a(n) for n = 1..155</a> %e A197249 Some solutions containing all values 0 to 4 for n=4 %e A197249 ..1..2..0..1..1..2..0....0..2..1..0..1..1..2....2..1..2..2..1..2..0 %e A197249 ..0..1..3..1..0..1..1....2..1..4..1..2..0..1....1..0..1..1..0..1..1 %e A197249 ..1..4..1..4..1..1..3....1..0..1..1..3..1..2....1..1..3..2..1..4..1 %e A197249 ..2..1..0..1..2..0..1....2..1..1..0..1..2..0....0..2..1..0..1..1..0 %K A197249 nonn %O A197249 1,1 %A A197249 _R. H. Hardin_ Oct 12 2011