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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.
1

%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