A233084 - OEIS

%I #8 Oct 07 2018 08:36:22

%S 10,122,1985,32414,529862,8662343,141615905,2315203034,37850025182,

%T 618789971363,10116268804625,165385509256454,2703799908891302,

%U 44202989610119183,722651215442080145,11814241158484224674

%N Number of 3 X n 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 in row major order.

%H R. H. Hardin, <a href="/A233084/b233084.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 19*a(n-1) - 45*a(n-2) + 27*a(n-3) for n>5.

%F Empirical g.f.: x*(10 - 68*x + 117*x^2 - 81*x^3 + 27*x^4) / ((1 - x)*(1 - 18*x + 27*x^2)). - _Colin Barker_, Oct 07 2018

%e Some solutions for n=4:

%e ..0..1..0..2....0..1..1..3....0..1..3..1....0..1..3..2....0..1..0..2

%e ..1..0..0..0....1..1..3..3....0..1..3..3....1..3..2..3....0..0..0..0

%e ..1..0..0..2....1..3..3..2....3..3..1..1....3..3..3..2....1..0..1..0

%Y Row 3 of A233082.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 03 2013