A303882 - OEIS

%I #6 Dec 29 2023 11:48:02

%S 1,4,8,24,82,272,908,3076,10444,35480,120648,410432,1396424,4751472,

%T 16168096,55017104,187214896,637067040,2167858112,7376953152,

%U 25102872672,85422038784,290680899264,989152113472,3365965684288,11453976585344

%N Number of n X 2 0..1 arrays with every element unequal to 0, 2, 3 or 4 king-move adjacent elements, with upper left element zero.

%C Column 2 of A303888.

%H R. H. Hardin, <a href="/A303882/b303882.txt">Table of n, a(n) for n = 1..210</a>

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

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A303888.

%K nonn

%O 1,2

%A _R. H. Hardin_, May 02 2018