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 A188986 #8 May 01 2018 09:37:47 %S A188986 7,49,295,1793,10871,65937,399911,2425505,14710935,89223345,541148807, %T A188986 3282123457,19906418039,120734483153,732267120743,4441275782369, %U A188986 26936796718423,163374456576241,990882967287879,6009807624994561 %N A188986 Number of n X 3 binary arrays without the pattern 0 0 1 antidiagonally or horizontally. %C A188986 Column 3 of A188992. %H A188986 R. H. Hardin, <a href="/A188986/b188986.txt">Table of n, a(n) for n = 1..200</a> %F A188986 Empirical: a(n) = 6*a(n-1) +a(n-2) -4*a(n-3) +2*a(n-4). %F A188986 Empirical g.f.: x*(7 + 7*x - 6*x^2 + 2*x^3) / ((1 + x)*(1 - 7*x + 6*x^2 - 2*x^3)). - _Colin Barker_, May 01 2018 %e A188986 Some solutions for 4 X 3: %e A188986 ..1..0..0....0..1..0....0..0..0....1..1..0....0..0..0....1..0..0....1..0..0 %e A188986 ..1..1..1....0..1..0....0..1..0....1..0..0....0..1..1....1..0..1....1..0..0 %e A188986 ..0..0..0....1..1..0....1..1..1....0..1..1....1..0..0....0..1..1....0..0..0 %e A188986 ..0..1..1....1..1..0....0..0..0....0..1..1....1..0..0....1..0..0....0..1..1 %Y A188986 Cf. A188992. %K A188986 nonn %O A188986 1,1 %A A188986 _R. H. Hardin_, Apr 15 2011