A204146 - OEIS

%I #8 Jun 06 2018 09:05:22

%S 689,3902,22262,127022,724154,4128422,23538722,134209022,765199994,

%T 4362829142,24874945682,141826072622,808630145834,4610454909062,

%U 26286795128642,149875795721822,854526159123674,4872133976736182

%N Number of (n+2) X 3 0..2 arrays with every 3 X 3 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..2 introduced in row major order.

%C Column 1 of A204153.

%H R. H. Hardin, <a href="/A204146/b204146.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) -5*a(n-2) +20*a(n-3) -4*a(n-4) -16*a(n-5).

%F Empirical g.f.: x*(689 - 232*x + 2295*x^2 - 820*x^3 - 1952*x^4) / ((1 - x)*(1 + 4*x^2)*(1 - 5*x - 4*x^2)). - _Colin Barker_, Jun 06 2018

%e Some solutions for n=4:

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

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

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

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

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

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

%Y Cf. A204153.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 11 2012