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 A206872 Number of 3 X n 0..1 arrays avoiding 0 0 0 horizontally and 1 0 1 vertically. 2

%I

%S 7,49,211,1153,6139,31529,165783,867545,4529439,23698777,123917699,

%T 647878921,3387923179,17715041713,92629806615,484357042545,

%U 2532662234303,13243089222385,69247131747475,362087861614577,1893329530949883

%N Number of 3 X n 0..1 arrays avoiding 0 0 0 horizontally and 1 0 1 vertically.

%C Row 3 of A206871.

%H R. H. Hardin, <a href="/A206872/b206872.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) + 7*a(n-2) + 27*a(n-3) - 13*a(n-4) + a(n-5) - 31*a(n-6) + 5*a(n-7) - 2*a(n-8) + 4*a(n-9).

%F Empirical g.f.: x*(7 + 28*x + 15*x^2 - 12*x^3 - 29*x^4 - 26*x^5 + 3*x^6 + 2*x^7 + 4*x^8) / ((1 - x)*(1 - 2*x - 9*x^2 - 36*x^3 - 23*x^4 - 24*x^5 + 7*x^6 + 2*x^7 + 4*x^8)). - _Colin Barker_, Mar 04 2018

%e Some solutions for n=4:

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

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

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

%Y Cf. A206871.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 13 2012

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Last modified May 17 23:07 EDT 2022. Contains 353779 sequences. (Running on oeis4.)