%I #4 Mar 25 2018 11:35:06

%S 1,10,30,118,407,1498,5289,19184,68832,247756,890523,3203084,11517675,

%T 41422044,148957388,535680672,1926390947,6927645818,24912983963,

%U 89591402294,322185988646,1158636174394,4166654317703,14984004032116

%N Number of nX3 0..1 arrays with every element equal to 1, 2 or 4 horizontally or vertically adjacent elements, with upper left element zero.

%C Column 3 of A301669.

%H R. H. Hardin, <a href="/A301664/b301664.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) +6*a(n-2) -2*a(n-4) +2*a(n-5) -9*a(n-6) -50*a(n-7) -37*a(n-8) +34*a(n-9) +43*a(n-10) -16*a(n-11) +15*a(n-12) +18*a(n-13) -7*a(n-14) -2*a(n-16) +4*a(n-17) -6*a(n-18) +a(n-20)

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A301669.

%K nonn

%O 1,2

%A _R. H. Hardin_, Mar 25 2018