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 A222682 #5 Jul 23 2025 02:55:30 %S A222682 15,18,130,527,5374,58167,687222,11377192,157746714,2877417604, %T A222682 41716355254,762816679067,11260740512076,204256746622744, %U A222682 3052246394940308 %N A222682 Number of 4Xn 0..3 arrays with no more than floor(4Xn/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..3 order. %C A222682 Row 4 of A222679 %e A222682 Some solutions for n=3 %e A222682 ..0..0..0....0..0..0....0..0..1....0..0..0....0..0..0....0..0..0....0..0..0 %e A222682 ..0..0..1....0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..0..0 %e A222682 ..1..0..0....0..0..1....0..0..0....1..0..2....0..0..1....0..0..0....0..0..1 %e A222682 ..0..0..0....2..0..2....0..0..0....0..0..0....2..0..3....0..0..2....2..0..1 %K A222682 nonn %O A222682 1,1 %A A222682 _R. H. Hardin_ Feb 28 2013