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 A205583 #9 Mar 04 2018 06:05:34 %S A205583 14,74,413,2268,12574,69338,383440,2117054,11699556,64620690, %T A205583 357034452,1972284262,10896200940,60194058786,332543162084, %U A205583 1837101323030,10149009487404,56067475332178,309742091323076,1711151039052838 %N A205583 Number of (n+1) X 2 0..2 arrays with no 2 X 2 subblock having the same number of equal edges as its horizontal or vertical neighbors, and new values 0..2 introduced in row major order. %C A205583 Column 1 of A205590. %H A205583 R. H. Hardin, <a href="/A205583/b205583.txt">Table of n, a(n) for n = 1..210</a> %F A205583 Empirical: a(n) = 21*a(n-2) + 44*a(n-3) + 50*a(n-4) + 12*a(n-5) - 144*a(n-6) for n>7. %F A205583 Empirical g.f.: x*(14 + 74*x + 119*x^2 + 98*x^3 - 55*x^4 - 330*x^5 + 72*x^6) / (1 - 21*x^2 - 44*x^3 - 50*x^4 - 12*x^5 + 144*x^6). - _Colin Barker_, Mar 04 2018 %e A205583 Some solutions for n=4: %e A205583 ..0..1....0..0....0..1....0..0....0..0....0..0....0..0....0..1....0..1....0..1 %e A205583 ..1..1....1..2....0..2....0..1....0..1....1..1....1..2....2..2....2..0....2..0 %e A205583 ..0..2....0..1....2..0....2..0....2..1....1..1....2..2....1..2....1..0....0..0 %e A205583 ..2..2....1..1....0..0....1..0....2..1....1..0....1..0....0..2....2..1....2..1 %e A205583 ..1..0....2..0....1..2....0..2....0..1....1..2....1..1....2..2....0..1....2..1 %Y A205583 Cf. A205590. %K A205583 nonn %O A205583 1,1 %A A205583 _R. H. Hardin_, Jan 29 2012