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 A197474 #7 Jun 02 2025 04:56:56 %S A197474 5,98,1300,10934,151748,1265828,16544206,145244408,1830370547, %T A197474 16537658774,202870487557,1878224690406,22527034080238, %U A197474 212875475502774,2505004507267645,24087191716817350,278905922435987885 %N A197474 Number of nX7 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 0,1,0,0,0 for x=0,1,2,3,4. %C A197474 Every 0 is next to 0 0's, every 1 is next to 1 1's, every 2 is next to 2 0's, every 3 is next to 3 0's, every 4 is next to 4 0's %C A197474 Column 7 of A197475 %H A197474 R. H. Hardin, <a href="/A197474/b197474.txt">Table of n, a(n) for n = 1..200</a> %e A197474 Some solutions containing all values 0 to 4 for n=4 %e A197474 ..2..0..1..1..0..3..0....1..0..3..0..2..1..1....1..1..2..0..1..2..0 %e A197474 ..0..4..0..2..1..0..3....1..2..0..4..0..2..0....0..3..0..2..1..0..3 %e A197474 ..1..0..4..0..1..2..0....0..2..1..0..3..1..2....3..0..3..1..0..4..0 %e A197474 ..1..2..0..3..0..1..1....2..0..1..2..0..1..0....0..3..0..1..2..0..2 %K A197474 nonn %O A197474 1,1 %A A197474 _R. H. Hardin_ Oct 15 2011