A318031 - OEIS

%I #4 Aug 13 2018 14:21:15

%S 2,3,6,11,22,46,91,182,371,746,1498,3027,6102,12283,24766,49926,

%T 100587,202726,408611,823442,1659506,3344611,6740518,13584427,

%U 27377702,55175838,111198651,224105366,451652627,910240506,1834460106,3697093427

%N Number of nX2 0..1 arrays with every element unequal to 0, 1, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 2 of A318037.

%H R. H. Hardin, <a href="/A318031/b318031.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +4*a(n-3) +a(n-5) -a(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..0

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

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

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

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

%Y Cf. A318037.

%K nonn

%O 1,1

%A _R. H. Hardin_, Aug 13 2018