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 A196474 #7 Jun 02 2025 04:24:51 %S A196474 8,18,17,70,151,557,2351,6926,16083,43523,126887,366749,1196290, %T A196474 3904083,12242778,35866180,101052064,296050389,899499517,2807496039, %U A196474 8933240984,27433666911,81672960692,242780272113,727008678986,2224880992862 %N A196474 Number of nX5 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 4,0,3,2,1 for x=0,1,2,3,4. %C A196474 Every 0 is next to 0 4's, every 1 is next to 1 0's, every 2 is next to 2 3's, every 3 is next to 3 2's, every 4 is next to 4 1's %C A196474 Column 5 of A196477 %H A196474 R. H. Hardin, <a href="/A196474/b196474.txt">Table of n, a(n) for n = 1..210</a> %e A196474 Some solutions for n=4 %e A196474 ..0..1..1..0..0....0..1..1..1..0....0..0..1..1..0....0..1..1..0..0 %e A196474 ..0..1..4..1..1....1..1..0..1..1....0..0..1..1..0....1..1..4..1..1 %e A196474 ..0..1..1..1..1....1..1..0..1..1....0..0..1..1..1....1..0..1..4..1 %e A196474 ..1..1..0..0..0....0..1..1..1..0....1..1..1..0..1....1..0..1..1..0 %K A196474 nonn %O A196474 1,1 %A A196474 _R. H. Hardin_ Oct 03 2011