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 A196855 #7 Jun 02 2025 04:35:20 %S A196855 40,6440,363685,28194191,2069281146,152929723254,11300853019444, %T A196855 835390769370971,61745852507376150,4563708721504197779, %U A196855 337310171120447151691,24931202561823495912020,1842711946915214490433763 %N A196855 Number of nX7 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,1,0,2,4 for x=0,1,2,3,4. %C A196855 Every 0 is next to 0 3's, every 1 is next to 1 1's, every 2 is next to 2 0's, every 3 is next to 3 2's, every 4 is next to 4 4's %C A196855 Column 7 of A196856 %H A196855 R. H. Hardin, <a href="/A196855/b196855.txt">Table of n, a(n) for n = 1..50</a> %e A196855 Some solutions for n=4 %e A196855 ..0..0..0..2..0..2..0....0..0..0..0..0..1..0....0..0..0..2..0..1..1 %e A196855 ..0..0..0..2..0..1..2....0..0..0..0..0..1..2....0..0..0..2..2..0..0 %e A196855 ..0..0..2..3..2..1..0....0..0..0..0..0..0..0....0..0..0..0..1..1..0 %e A196855 ..0..0..1..1..0..2..0....0..0..1..1..2..0..0....0..2..2..0..2..0..2 %K A196855 nonn %O A196855 1,1 %A A196855 _R. H. Hardin_ Oct 06 2011