A209807 - OEIS

%I #8 Jul 13 2018 05:33:28

%S 7,34,173,930,5193,29782,173789,1025274,6089457,36315262,217102757,

%T 1299807138,7788836985,46697385574,280057392749,1679892321738,

%U 10077743984769,60460730002126,362743958401973,2176391017766514

%N Number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having two distinct values, and new values 0..3 introduced in row major order.

%C Column 1 of A209814.

%H R. H. Hardin, <a href="/A209807/b209807.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 8*a(n-1) - 7*a(n-2) - 28*a(n-3) - 12*a(n-4).

%F Empirical g.f.: x*(7 - 22*x - 50*x^2 - 20*x^3) / ((1 + x)*(1 - 6*x)*(1 - 3*x - 2*x^2)). - _Colin Barker_, Jul 13 2018

%e Some solutions for n=4:

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

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

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

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

%e ..2..2....0..1....0..0....0..0....1..1....1..0....0..1....0..0....0..1....0..0

%Y Cf. A209814.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 13 2012