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 A197885 #7 Jun 02 2025 05:12:45 %S A197885 2,14,47,155,835,2263,10827,38938,157178,654028,2607334,10482745, %T A197885 41930639,169374587,686689100,2793219587,11244612740,45359859580, %U A197885 183328706973,742423862981,3008747408411,12158966386525,49114866456717 %N A197885 Number of nX4 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 0,2,1,1,1 for x=0,1,2,3,4. %C A197885 Every 0 is next to 0 0's, every 1 is next to 1 2'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 A197885 Column 4 of A197889 %H A197885 R. H. Hardin, <a href="/A197885/b197885.txt">Table of n, a(n) for n = 1..210</a> %e A197885 Some solutions containing all values 0 to 4 for n=5 %e A197885 ..2..1..0..1....2..1..1..2....2..1..1..2....0..1..2..1....0..1..1..2 %e A197885 ..1..3..1..2....1..4..1..1....1..1..4..1....2..1..3..1....1..2..0..1 %e A197885 ..0..2..1..0....0..1..2..0....0..2..1..0....1..4..1..2....0..2..1..3 %e A197885 ..1..1..4..1....2..1..0..1....1..3..1..2....0..1..1..0....1..1..4..1 %e A197885 ..2..1..1..2....1..3..1..2....2..1..3..1....1..2..2..1....2..1..1..2 %K A197885 nonn %O A197885 1,1 %A A197885 _R. H. Hardin_ Oct 19 2011