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 A183768 #7 Jan 14 2017 09:38:16 %S A183768 2016,5912192,19855042560,70577422755840,258888921984516096, %T A183768 968823452179344785408,3676119951496408119115776, %U A183768 14091184863095839321177456640,54435471052008802940182132162560 %N A183768 1/32 the number of (2n+1) X 6 binary arrays with equal numbers of 2 X 2 subblocks with sum mod two being 0 and 1. %C A183768 Column 5 of A183772(2n). %H A183768 R. H. Hardin, <a href="/A183768/b183768.txt">Table of n, a(n) for n = 1..65</a> %e A183768 Some solutions for 3 X 6: %e A183768 ..0..0..0..1..0..1....0..1..1..1..1..1....1..1..0..0..0..1....1..0..0..0..1..0 %e A183768 ..0..1..1..1..0..1....0..1..0..1..0..0....1..1..1..1..0..1....0..1..1..1..1..1 %e A183768 ..1..1..1..0..0..1....0..0..1..0..0..0....0..0..1..0..1..1....0..0..0..0..1..0 %K A183768 nonn %O A183768 1,1 %A A183768 _R. H. Hardin_, Jan 06 2011