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 A198526 #7 Jul 22 2025 12:59:33 %S A198526 202,1948672,26670041125,371815743708461,5186266567454077293, %T A198526 72341858272434900016248,1009078065869144136137180812, %U A198526 14075371934477934686865356966591,196333764385468923490801365319931630 %N A198526 Number of nX6 0..4 arrays with values 0..4 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors. %C A198526 Column 6 of A198528 %H A198526 R. H. Hardin, <a href="/A198526/b198526.txt">Table of n, a(n) for n = 1..11</a> %e A198526 Some solutions for n=4 %e A198526 ..0..0..0..1..2..0....0..0..0..1..1..1....0..0..0..1..0..1....0..0..0..1..0..2 %e A198526 ..1..1..0..0..1..1....1..1..0..0..2..2....1..1..0..0..1..1....1..1..0..0..2..3 %e A198526 ..0..0..1..0..1..0....0..0..1..0..2..1....0..0..1..0..2..2....0..0..1..0..4..1 %e A198526 ..0..0..1..0..2..3....0..0..1..0..1..0....0..0..1..0..0..2....0..0..1..0..0..1 %K A198526 nonn %O A198526 1,1 %A A198526 _R. H. Hardin_ Oct 26 2011