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 A197535 #7 Jan 20 2024 15:24:12 %S A197535 16,160,3500,62586,1220630,23325250,454280983,8844380028,172982554332, %T A197535 3386294190736,66356347688978,1300795127521094,25506585069158562, %U A197535 500211695453958433,9810478953775130079,192417797960470740096 %N A197535 Number of n X 6 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 A197535 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 A197535 Column 6 of A197537. %H A197535 R. H. Hardin, <a href="/A197535/b197535.txt">Table of n, a(n) for n = 1..210</a> %e A197535 Some solutions containing all values 0 to 4 for n=4: %e A197535 ..0..0..0..0..3..0....1..1..1..1..2..1....0..0..0..3..0..1....1..1..2..1..1..1 %e A197535 ..3..0..0..4..0..0....0..0..0..0..3..0....0..0..4..0..3..2....0..0..3..0..0..0 %e A197535 ..0..3..0..0..3..0....0..0..0..4..0..0....0..0..0..0..0..1....3..0..0..4..0..3 %e A197535 ..1..2..1..1..2..1....0..0..3..0..3..0....0..3..0..0..0..1....0..0..0..0..3..0 %Y A197535 Cf. A197537. %K A197535 nonn %O A197535 1,1 %A A197535 _R. H. Hardin_, Oct 16 2011