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A208014 Number of 4 X n 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 0 1 1 vertically. 1

%I

%S 9,81,225,841,2304,6084,18496,53824,150544,435600,1263376,3610000,

%T 10368400,29899024,85895824,246741264,709902736,2041232400,5866947216,

%U 16869853456,48507419536,139454446096,400947305616,1152814510864

%N Number of 4 X n 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 0 1 1 vertically.

%C Row 4 of A208013.

%H R. H. Hardin, <a href="/A208014/b208014.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) + 2*a(n-2) + 10*a(n-3) + 4*a(n-4) - 8*a(n-5) - 16*a(n-6) for n>8.

%F Empirical g.f.: x*(9 + 72*x + 126*x^2 + 364*x^3 + 167*x^4 - 404*x^5 - 714*x^6 - 148*x^7) / ((1 + 2*x^2 - 4*x^3)*(1 - x - 4*x^2 - 4*x^3)). - _Colin Barker_, Jun 26 2018

%e Some solutions for n=4:

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

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

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

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

%Y Cf. A208013.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 22 2012

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Last modified July 1 03:30 EDT 2022. Contains 354947 sequences. (Running on oeis4.)