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%I #8 Mar 06 2018 08:54:53
%S 6,36,102,270,798,2354,7210,22232,69570,218950,693810,2207142,7047274,
%T 22559004,72371822,232562110,748347990,2410664906,7772348106,
%U 25076879856,80954866538,261464311606,844780530762,2730274274910,8826217794378
%N Number of n X 3 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically.
%C Column 3 of A207752.
%H R. H. Hardin, <a href="/A207747/b207747.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 7*a(n-1) - 9*a(n-2) - 32*a(n-3) + 72*a(n-4) + 36*a(n-5) - 147*a(n-6) + 9*a(n-7) + 109*a(n-8) - 28*a(n-9) - 24*a(n-10) + 8*a(n-11) for n>12. Corrected by _Colin Barker_, Mar 06 2018
%F Empirical g.f.: 2*x*(3 - 3*x - 48*x^2 + 36*x^3 + 273*x^4 - 173*x^5 - 602*x^6 + 305*x^7 + 502*x^8 - 216*x^9 - 120*x^10 + 48*x^11) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - 3*x + x^2)*(1 + x - x^2)*(1 - x - x^2)*(1 - 2*x - 4*x^2)). - _Colin Barker_, Mar 06 2018
%e Some solutions for n=4:
%e ..0..0..0....1..1..1....1..1..0....0..0..0....0..0..0....1..0..1....1..1..0
%e ..1..1..1....1..1..1....0..1..0....1..0..1....0..1..0....1..0..1....1..0..1
%e ..0..0..0....0..1..0....1..0..0....0..0..0....0..1..0....1..0..0....1..1..0
%e ..1..1..1....1..1..1....0..1..0....1..0..1....0..0..0....1..0..1....1..0..1
%Y Cf. A207752.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 19 2012
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