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 A240646 #6 Jul 23 2025 11:04:40 %S A240646 3,6,23,61,232,953,4343,19458,90165,421048,1984496,9408853,44826507, %T A240646 214397042,1027671976,4934720969,23725826486,114171204929, %U A240646 549741892899,2648230058688,12761166119581,61506635738385,296498879827182 %N A240646 Number of nX5 0..1 arrays with no element equal to the same number of vertical neighbors as horizontal neighbors, with new values 0..1 introduced in row major order. %C A240646 Column 5 of A240649 %H A240646 R. H. Hardin, <a href="/A240646/b240646.txt">Table of n, a(n) for n = 1..210</a> %e A240646 Some solutions for n=4 %e A240646 ..0..1..0..0..1....0..1..0..1..0....0..0..0..0..0....0..1..0..1..1 %e A240646 ..0..1..1..1..1....0..1..0..1..0....1..0..0..0..1....0..1..0..0..0 %e A240646 ..0..1..1..1..1....1..0..1..0..1....1..0..1..0..1....0..0..0..0..1 %e A240646 ..0..1..0..0..1....1..0..1..0..1....1..0..1..0..1....0..1..1..0..1 %K A240646 nonn %O A240646 1,1 %A A240646 _R. H. Hardin_, Apr 09 2014