A275260 - OEIS

%I #7 Feb 02 2019 11:33:17

%S 2,9,24,64,172,476,1320,3672,10220,28472,79376,221320,617160,1720976,

%T 4799104,13382832,37319536,104069760,290210016,809282592,2256773088,

%U 6293258240,17549436800,48938515904,136470379968,380562509568

%N Number of n X 2 0..2 arrays with no element equal to any value at offset (-2,-1) (-2,1) or (-1,-1) and new values introduced in order 0..2.

%H R. H. Hardin, <a href="/A275260/b275260.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) - 2*a(n-2) - 6*a(n-3) + 6*a(n-4) + 4*a(n-5) - 16*a(n-6) + 12*a(n-7) + 8*a(n-8) - 8*a(n-9) for n>10.

%F Empirical g.f.: x*(2 + x - 8*x^2 - 2*x^3 + 6*x^4 - 2*x^5 - 4*x^6 + 16*x^7 - 8*x^9) / (1 - 4*x + 2*x^2 + 6*x^3 - 6*x^4 - 4*x^5 + 16*x^6 - 12*x^7 - 8*x^8 + 8*x^9). - _Colin Barker_, Feb 02 2019

%e Some solutions for n=4:

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

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

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

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

%Y Column 2 of A275266.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jul 21 2016