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 A188700 #10 Apr 28 2018 08:11:23 %S A188700 8,21,90,304,1141,4084,14925,54049,196508,713225,2590574,9406448, %T A188700 34159833,124045128,450458681,1635781681,5940155616,21570956189, %U A188700 78332387394,284454730240,1032963629229,3751084683708,13621618755397 %N A188700 Number of n X 3 binary arrays without the pattern 0 0 diagonally or vertically. %C A188700 Column 3 of A188706. %H A188700 R. H. Hardin, <a href="/A188700/b188700.txt">Table of n, a(n) for n = 1..200</a> %F A188700 Empirical: a(n) = a(n-1) + 8*a(n-2) + 6*a(n-3) - a(n-4) - a(n-5). %F A188700 Empirical g.f.: x*(8 + 13*x + 5*x^2 - 2*x^3 - x^4) / ((1 + x)*(1 - 2*x - 6*x^2 + x^4)). - _Colin Barker_, Apr 28 2018 %e A188700 Some solutions for 4 X 3: %e A188700 ..1..1..1....0..0..1....1..1..0....1..1..1....0..1..1....0..0..0....1..1..1 %e A188700 ..1..0..1....1..1..1....1..1..1....0..1..1....1..1..0....1..1..1....0..1..0 %e A188700 ..1..1..1....1..1..1....0..0..1....1..1..1....1..1..1....0..1..1....1..1..1 %e A188700 ..1..0..1....1..1..0....1..1..1....0..1..1....1..0..0....1..1..1....0..1..1 %Y A188700 Cf. A188706. %K A188700 nonn %O A188700 1,1 %A A188700 _R. H. Hardin_, Apr 08 2011