A230676 - OEIS

A230676

Number of 2 X n 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value 2-x(i,j).

%I #8 Sep 22 2018 10:53:25

%S 0,15,87,513,3387,21933,141411,913245,5898099,38088477,245968275,

%T 1588424445,10257784563,66243081501,427786930899,2762577674301,

%U 17840272397235,115209545904477,744004305214611,4804657476983421

%N Number of 2 X n 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value 2-x(i,j).

%H R. H. Hardin, <a href="/A230676/b230676.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 5*a(n-1) + 6*a(n-2) + 20*a(n-3) + 12*a(n-4) + 8*a(n-5).

%F Empirical g.f.: 3*x^2*(5 + 4*x - 4*x^2) / (1 - 5*x - 6*x^2 - 20*x^3 - 12*x^4 - 8*x^5). - _Colin Barker_, Sep 22 2018

%e Some solutions for n=3:

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

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

%Y Row 2 of A230675.

%K nonn

%O 1,2

%A _R. H. Hardin_, Oct 27 2013