A183684 - OEIS

%I #10 Apr 04 2018 10:48:22

%S 96,528,2688,14144,73344,382848,1992320,10382976,54072960,281700992,

%T 1467309696,7643513472,39814841984,207399103104,1080347897472,

%U 5627597738624,29314404685440,152700279978624,795423120883328

%N Number of (n+1) X 6 binary arrays with every 2 X 2 subblock nonsingular.

%C Column 5 of A183688.

%H R. H. Hardin, <a href="/A183684/b183684.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 3*a(n-1) + 18*a(n-2) - 20*a(n-3) - 72*a(n-4).

%F Empirical g.f.: 16*x*(6 + 15*x - 39*x^2 - 94*x^3) / ((1 + 2*x)*(1 - 5*x - 8*x^2 + 36*x^3)). - _Colin Barker_, Apr 04 2018

%e Some solutions for 3 X 6:

%e ..0..1..1..0..1..0....1..0..1..1..0..1....0..1..0..1..0..1....1..1..0..1..1..0

%e ..1..0..1..1..1..1....0..1..0..1..1..0....1..1..1..1..1..0....1..0..1..0..1..1

%e ..0..1..1..0..1..0....1..0..1..0..1..1....0..1..0..1..0..1....0..1..1..1..1..0

%Y Cf. A183688.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 06 2011