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%I #8 Mar 05 2018 11:21:04
%S 6,36,114,387,1414,5302,20265,78120,302850,1177545,4587102,17888094,
%T 69803695,272499292,1064042682,4155446955,16229927982,63392825886,
%U 247616093433,967223892240,3778165401850,14758373590129,57649858583478
%N Number of n X 3 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 0 0 vertically.
%C Column 3 of A207717.
%H R. H. Hardin, <a href="/A207712/b207712.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 6*a(n-1) - 4*a(n-2) - 23*a(n-3) + 20*a(n-4) + 28*a(n-5) - 13*a(n-6) - 14*a(n-7) + a(n-9) for n>10.
%F Empirical g.f.: x*(6 - 78*x^2 - 15*x^3 + 256*x^4 + 100*x^5 - 200*x^6 - 120*x^7 + 6*x^8 + 9*x^9) / ((1 - x)*(1 - x - x^2)*(1 - 2*x - x^2)*(1 - 2*x - 7*x^2 - 2*x^3 + x^4)). - _Colin Barker_, Mar 05 2018
%e Some solutions for n=4:
%e ..1..1..1....1..1..0....0..1..1....1..0..0....1..1..1....0..1..0....1..0..0
%e ..1..1..1....1..1..0....1..1..0....0..1..0....1..0..1....0..1..1....0..1..1
%e ..1..1..1....1..0..0....0..1..1....1..0..0....1..1..1....0..1..1....1..1..0
%e ..1..1..0....1..1..0....1..1..0....0..1..0....0..1..1....0..1..0....1..1..1
%Y Cf. A207717.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 19 2012
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