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 A184466 #7 Jul 22 2025 09:34:57 %S A184466 16809,5002165,2002023718,873679701315,396770571117114, %T A184466 184478487695574108,87131390011496951676,41619801566809753837565, %U A184466 20050042433422012129360190,9723279387982947487498511078 %N A184466 Half the number of (n+1)X9 binary arrays with equal numbers of majority one 2X2 subblocks and majority zero 2X2 subblocks. %C A184466 Column 8 of A184467 %H A184466 R. H. Hardin, <a href="/A184466/b184466.txt">Table of n, a(n) for n = 1..18</a> %e A184466 Some solutions for 3X9 %e A184466 ..0..0..1..1..1..1..1..0..0....0..0..1..1..0..1..1..1..0 %e A184466 ..0..0..0..1..0..0..1..1..1....0..0..0..1..0..0..1..1..0 %e A184466 ..0..0..1..1..0..0..0..0..1....0..0..0..1..1..1..0..1..0 %e A184466 ... %e A184466 ...M..M..P..P..E..P..P..E.......M..M..P..E..M..P..P..E... %e A184466 ...M..M..P..E..M..M..E..P.......M..M..E..P..E..E..P..E... %K A184466 nonn %O A184466 1,1 %A A184466 _R. H. Hardin_ Jan 15 2011