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 A222375 #6 Jul 23 2025 02:32:51 %S A222375 4,18,118,1391,20340,342953,6221698,113556454,2103238076,38940850866, %T A222375 724814585064,13496985711211,251700828899740,4703187944642436, %U A222375 87873606070564444,1646203673458642042,30815057060615530576 %N A222375 Number of nX4 0..3 arrays with no more than floor(nX4/2) elements unequal to at least one horizontal or vertical neighbor, with new values introduced in row major 0..3 order. %C A222375 Column 4 of A222378 %H A222375 R. H. Hardin, <a href="/A222375/b222375.txt">Table of n, a(n) for n = 1..50</a> %e A222375 Some solutions for n=4 %e A222375 ..0..0..0..0....0..0..1..0....0..0..0..0....0..0..0..0....0..0..1..1 %e A222375 ..0..0..0..0....0..0..2..1....0..0..0..0....0..0..0..0....0..1..1..1 %e A222375 ..0..0..0..0....0..0..0..0....0..1..0..2....1..2..0..0....2..1..1..1 %e A222375 ..1..1..2..2....0..0..0..0....0..0..0..0....2..3..0..0....2..2..1..1 %K A222375 nonn %O A222375 1,1 %A A222375 _R. H. Hardin_ Feb 17 2013