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A184369 1/3 the number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock having at least two equal elements connected horizontally or vertically.

%I A184369 #8 Feb 27 2018 08:59:05
%S A184369 153,2755,49235,880781,15754461,281803871,5040682279,90163722073,
%T A184369 1612776998193,28848073268443,516011408652059,9230001997285733,
%U A184369 165098940527912805,2953158641948611223,52823754874667184367
%N A184369 1/3 the number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock having at least two equal elements connected horizontally or vertically.
%C A184369 Column 2 of A184376.
%H A184369 R. H. Hardin, <a href="/A184369/b184369.txt">Table of n, a(n) for n = 1..200</a>
%F A184369 Empirical: a(n) = 17*a(n-1) + 19*a(n-2) - 57*a(n-3) + 18*a(n-4).
%F A184369 Empirical g.f.: x*(153 + 154*x - 507*x^2 + 162*x^3) / (1 - 17*x - 19*x^2 + 57*x^3 - 18*x^4). - _Colin Barker_, Feb 27 2018
%e A184369 Some solutions for 5 X 3 with a(1,1)=0:
%e A184369 ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0
%e A184369 ..1..0..2....1..2..2....0..1..0....0..2..2....1..1..1....0..2..0....1..1..0
%e A184369 ..1..2..2....0..2..0....1..1..1....1..1..2....1..2..0....1..2..0....1..0..0
%e A184369 ..1..2..2....1..1..0....2..1..2....2..1..2....1..1..1....1..2..0....2..2..2
%e A184369 ..1..1..1....2..2..2....0..1..0....0..0..0....0..2..0....0..2..1....0..2..0
%Y A184369 Cf. A184376.
%K A184369 nonn
%O A184369 1,1
%A A184369 _R. H. Hardin_, Jan 12 2011