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 A188701 #9 Apr 28 2018 08:12:05 %S A188701 16,55,387,1876,10857,57665,318732,1729531,9464035,51591068,281717653, %T A188701 1537169293,8390298820,45789639603,249911548135,1363931051824, %U A188701 7443964229917,40626890315469,221729775973184,1210135365944631 %N A188701 Number of n X 4 binary arrays without the pattern 0 0 diagonally or vertically. %C A188701 Column 4 of A188706. %H A188701 R. H. Hardin, <a href="/A188701/b188701.txt">Table of n, a(n) for n = 1..200</a> %F A188701 Empirical: a(n) = a(n-1) + 20*a(n-2) + 27*a(n-3) - 14*a(n-4) - 25*a(n-5) + 4*a(n-6) + 5*a(n-7) - a(n-8). %F A188701 Empirical g.f.: x*(16 + 39*x + 12*x^2 - 43*x^3 - 20*x^4 + 9*x^5 + 4*x^6 - x^7) / ((1 + x)*(1 + 2*x - x^2)*(1 - 4*x - 9*x^2 + 5*x^3 + 4*x^4 - x^5)). - _Colin Barker_, Apr 28 2018 %e A188701 Some solutions for 3 X 4: %e A188701 ..0..0..1..0....1..1..0..0....1..1..0..1....1..1..1..1....1..1..0..0 %e A188701 ..1..1..1..1....1..1..1..1....1..0..1..1....1..1..1..0....0..1..1..1 %e A188701 ..0..0..0..0....0..1..1..0....1..1..1..1....0..1..1..1....1..1..0..0 %Y A188701 Cf. A188706. %K A188701 nonn %O A188701 1,1 %A A188701 _R. H. Hardin_, Apr 08 2011