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 A196135 #7 Jun 02 2025 04:17:33 %S A196135 1,14,31,165,326,1350,3288,12943,33772,113604,328378,1119797,3245707, %T A196135 10352649,31244339,100779085,304866170,952470015,2927610616, %U A196135 9231448285,28362649959,88098662332,272473939620,851211806848,2631049299378 %N A196135 Number of nX5 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 0,2,1,3,4 for x=0,1,2,3,4. %C A196135 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 3's, every 4 is next to 4 4's %C A196135 Column 5 of A196138 %H A196135 R. H. Hardin, <a href="/A196135/b196135.txt">Table of n, a(n) for n = 1..200</a> %e A196135 Some solutions for n=4 %e A196135 ..0..1..2..0..1....1..0..2..1..1....2..1..0..2..1....2..1..1..2..1 %e A196135 ..1..0..1..1..2....2..1..1..1..2....1..0..1..1..0....1..1..1..2..0 %e A196135 ..2..1..1..1..0....2..1..1..1..2....1..1..2..0..1....1..2..0..1..1 %e A196135 ..0..1..2..2..1....1..1..2..0..1....2..1..0..1..2....1..2..1..1..2 %K A196135 nonn %O A196135 1,2 %A A196135 _R. H. Hardin_ Sep 28 2011