%I #4 Apr 17 2018 13:24:25
%S 4,6,14,28,56,150,360,828,1906,4628,10972,25850,60948,145152,343870,
%T 814072,1927632,4573086,10836712,25678860,60851842,144253956,
%U 341881772,810275098,1920403380,4551789280,10788216718,25569422984,60602792000
%N Number of 3Xn 0..1 arrays with every element equal to 0, 1, 3, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
%C Row 3 of A303040.
%H R. H. Hardin, <a href="/A303041/b303041.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) +2*a(n-2) -2*a(n-3) +6*a(n-4) -16*a(n-5) -11*a(n-6) +14*a(n-7) -4*a(n-8) +16*a(n-9) +4*a(n-10) -8*a(n-11) for n>12
%e Some solutions for n=5
%e ..0..1..0..1..0. .0..1..0..1..0. .0..1..0..1..0. .0..1..0..1..1
%e ..1..1..0..0..0. .0..1..1..1..0. .0..1..0..1..0. .0..1..0..0..0
%e ..0..1..0..1..0. .0..1..0..1..0. .0..1..1..1..0. .0..1..1..1..0
%Y Cf. A303040.
%K nonn
%O 1,1
%A _R. H. Hardin_, Apr 17 2018