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 A205186 #11 Jan 19 2018 05:11:36 %S A205186 16,40,124,256,736,1408,3904,7168,19456,34816,93184,163840,434176, %T A205186 753664,1982464,3407872,8912896,15204352,39583744,67108864,174063616, %U A205186 293601280,759169024,1275068416,3288334336 %N A205186 Number of (n+1) X (n+1) 0..1 arrays with the number of clockwise edge increases in every 2 X 2 subblock differing from each horizontal or vertical neighbor. %C A205186 Diagonal of A205193. %F A205186 Conjectures from _Colin Barker_, Jan 17 2018: (Start) %F A205186 G.f.: 4*x*(4 + 10*x - x^2 - 16*x^3) / ((1 - 2*x)^2*(1 + 2*x)^2). %F A205186 a(n) = 8*a(n-2) - 16*a(n-4) for n>3. %F A205186 (End) %e A205186 Some solutions for n=4: %e A205186 0 0 1 0 1 0 0 1 1 0 0 1 0 0 0 1 0 1 0 0 %e A205186 0 0 0 1 1 0 0 1 1 0 1 0 0 0 1 1 1 0 0 0 %e A205186 1 0 0 1 1 1 1 0 0 1 0 0 0 1 0 1 1 0 0 1 %e A205186 0 1 1 0 0 1 1 0 0 0 0 0 1 0 0 1 0 1 1 0 %e A205186 0 1 1 0 0 0 0 1 0 0 0 1 0 0 0 0 1 1 1 0 %K A205186 nonn %O A205186 1,1 %A A205186 _R. H. Hardin_, Jan 23 2012