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 A183766 #7 Jan 14 2017 01:53:33 %S A183766 40,7392,1555840,346131968,79420170240,18585877094400, %T A183766 4409408507412480,1056689477487820800,255189244398549336064, %U A183766 62004700939478066266112,15140238779254079729172480,3712064235466595220724908032 %N A183766 1/32 the number of (2n+1) X 4 binary arrays with equal numbers of 2 X 2 subblocks with sum mod two being 0 and 1. %C A183766 Column 3 of A183772(2n). %H A183766 Ron Hardin, <a href="/A183766/b183766.txt">Table of n, a(n) for n = 1..100</a> %e A183766 Some solutions for 3 X 4: %e A183766 ..1..0..1..0....0..0..0..0....0..1..1..1....0..0..0..1....1..0..0..1 %e A183766 ..0..1..1..0....0..1..1..0....0..1..0..1....1..0..1..0....0..0..1..0 %e A183766 ..0..1..0..0....0..1..0..1....0..1..1..0....1..1..0..1....1..1..1..0 %K A183766 nonn %O A183766 1,1 %A A183766 _R. H. Hardin_, Jan 06 2011