cp's OEIS Frontend

A183685 Number of (n+1) X 7 binary arrays with every 2 X 2 subblock nonsingular.

%I A183685 #9 Apr 04 2018 10:48:18
%S A183685 192,1360,8704,58448,382848,2542368,16748160,110871040,731709056,
%T A183685 4838473472,31954317952,211206670208,1395251843712,9220409667200,
%U A183685 60918293373568,402541765541504,2659689937121920,17574356285235840
%N A183685 Number of (n+1) X 7 binary arrays with every 2 X 2 subblock nonsingular.
%C A183685 Column 6 of A183688.
%H A183685 R. H. Hardin, <a href="/A183685/b183685.txt">Table of n, a(n) for n = 1..200</a>
%F A183685 Empirical: a(n) = 3*a(n-1) + 48*a(n-2) - 78*a(n-3) - 720*a(n-4) + 612*a(n-5) + 4232*a(n-6) - 1392*a(n-7) - 8192*a(n-8).
%F A183685 Empirical g.f.: 16*x*(12 + 49*x - 287*x^2 - 1123*x^3 + 2127*x^4 + 8058*x^5 - 4668*x^6 - 17344*x^7) / (1 - 3*x - 48*x^2 + 78*x^3 + 720*x^4 - 612*x^5 - 4232*x^6 + 1392*x^7 + 8192*x^8). - _Colin Barker_, Apr 04 2018
%e A183685 Some solutions for 3 X 7:
%e A183685 ..0..1..1..1..0..1..1....1..1..1..1..0..1..1....1..1..0..1..0..1..0
%e A183685 ..1..1..0..1..1..0..1....1..0..1..0..1..0..1....0..1..1..1..1..0..1
%e A183685 ..0..1..1..1..0..1..1....1..1..1..1..1..1..0....1..0..1..0..1..1..1
%Y A183685 Cf. A183688.
%K A183685 nonn
%O A183685 1,1
%A A183685 _R. H. Hardin_, Jan 06 2011