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 A205253 #7 Jul 22 2025 18:41:53 %S A205253 2920,71000,1764364,44183032,1109832184,27913330476,702420750928, %T A205253 17679917387408,445045123432100,11203277447970640,282028756620227128, %U A205253 7099777698513424924,178729975670304808352,4499358353656818662432 %N A205253 Number of (n+1)X7 0..1 arrays with the number of clockwise edge increases in every 2X2 subblock the same. %C A205253 Column 6 of A205255 %H A205253 R. H. Hardin, <a href="/A205253/b205253.txt">Table of n, a(n) for n = 1..210</a> %F A205253 Empirical: a(n) = 56*a(n-1) -1164*a(n-2) +12439*a(n-3) -78536*a(n-4) +314610*a(n-5) -829844*a(n-6) +1464316*a(n-7) -1728640*a(n-8) +1345964*a(n-9) -671600*a(n-10) +205552*a(n-11) -36416*a(n-12) +3392*a(n-13) -128*a(n-14) %e A205253 Some solutions for n=4 %e A205253 ..0..1..0..0..1..0..1....0..1..1..1..0..0..1....1..1..0..0..0..0..1 %e A205253 ..1..1..0..1..1..0..0....0..1..0..0..0..1..1....1..0..0..1..0..1..1 %e A205253 ..0..0..0..0..1..1..0....1..1..1..0..1..1..0....1..0..1..1..1..1..0 %e A205253 ..0..1..0..1..1..0..0....1..0..1..0..0..0..0....1..1..1..0..1..0..0 %e A205253 ..0..0..0..1..0..0..1....0..0..1..0..1..1..1....1..0..0..0..0..0..1 %K A205253 nonn %O A205253 1,1 %A A205253 _R. H. Hardin_ Jan 24 2012