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%I #8 Nov 02 2018 12:24:41
%S 13,35,96,265,733,2029,5618,15557,43081,119303,330384,914929,2533705,
%T 7016569,19430930,53809925,149015413,412667243,1142796240,3164736889,
%U 8764081669,24270304357,67211568290,186128482181,515444182609
%N Number of length n+3 0..2 arrays with no four elements in a row with pattern abba (with a!=b) and new values 0..2 introduced in 0..2 order.
%H R. H. Hardin, <a href="/A243383/b243383.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) - 4*a(n-2) + 2*a(n-3) - a(n-4).
%F Empirical g.f.: x*(13 - 17*x + 8*x^2 - 5*x^3) / ((1 - x)*(1 - 3*x + x^2 - x^3)). - _Colin Barker_, Nov 02 2018
%e Some solutions for n=3:
%e ..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
%e ..0....0....0....1....0....1....1....1....0....1....1....1....0....0....0....0
%e ..0....1....1....0....1....2....0....1....0....0....0....2....1....1....1....1
%e ..1....2....1....2....0....0....2....1....1....2....2....2....2....2....0....2
%e ..0....2....2....0....1....2....1....1....2....1....1....2....1....0....2....1
%e ..1....2....2....0....0....0....0....2....0....1....2....0....0....0....2....1
%Y Column 2 of A243389.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jun 04 2014
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