%I #10 Jul 29 2020 23:14:13

%S 2,4,8,18,38,82,176,378,812,1744,3746,8046,17282,37120,79730,171252,

%T 367832,790066,1696982,3644946,7828976,16815850,36118748,77579424,

%U 166632770,357910366,768755330,1651208832,3546629858,7617802852

%N Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random 0..1 n X 2 array.

%C Column 2 of A218084.

%H R. H. Hardin, <a href="/A218078/b218078.txt">Table of n, a(n) for n = 1..210</a>

%H Todd Mullen, <a href="https://dalspace.library.dal.ca/bitstream/handle/10222/78458/Mullen-Todd-PhD-MATH-April-2020.pdf">On Variants of Diffusion</a>, Dalhousie University (Halifax, NS Canada, 2020).

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

%F Empirical g.f.: 2*x*(1 + x) / (1 - x - 2*x^2 - x^3). - _Colin Barker_, Jul 24 2018

%e All solutions for n=3:

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

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

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

%Y Cf. A218084.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 20 2012