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 A197534 #7 Jun 02 2025 04:58:51 %S A197534 9,73,868,9373,107655,1220630,14056707,162042137,1874230689, %T A197534 21698542215,251403042154,2913819348602,33779087426950, %U A197534 391635814747885,4540933400612193,52653016886940873,610534294176601038 %N A197534 Number of nX5 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,0,1,0,0 for x=0,1,2,3,4. %C A197534 Every 0 is next to 0 2's, every 1 is next to 1 0's, every 2 is next to 2 1's, every 3 is next to 3 0's, every 4 is next to 4 0's %C A197534 Column 5 of A197537 %H A197534 R. H. Hardin, <a href="/A197534/b197534.txt">Table of n, a(n) for n = 1..210</a> %e A197534 Some solutions containing all values 0 to 4 for n=4 %e A197534 ..1..0..0..0..0....0..0..1..1..2....0..3..0..0..1....0..0..0..0..0 %e A197534 ..1..0..4..0..0....0..0..3..0..1....3..0..4..0..1....0..4..0..3..0 %e A197534 ..2..3..0..0..3....0..4..0..3..2....0..3..0..3..2....3..0..0..1..1 %e A197534 ..1..0..0..3..0....0..0..3..0..1....1..1..0..0..1....0..3..0..1..2 %K A197534 nonn %O A197534 1,1 %A A197534 _R. H. Hardin_ Oct 16 2011