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%I #8 Nov 01 2018 11:39:23
%S 13,42,147,536,1987,7414,27736,103868,389129,1458054,5463618,20473754,
%T 76721788,287502448,1077370309,4037278442,15129079265,56693899710,
%U 212451684345,796130077586,2983375282018,11179741027060,41894363838109
%N Number of length n+3 0..3 arrays with no four elements in a row with pattern abba (possibly a=b) and new values 0..3 introduced in 0..3 order.
%H R. H. Hardin, <a href="/A243028/b243028.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) - a(n-2) + 2*a(n-3) - 6*a(n-4) - 2*a(n-5) - 3*a(n-6).
%F Empirical g.f.: x*(13 - 10*x - 8*x^2 - 36*x^3 - 16*x^4 - 14*x^5) / ((1 - x - x^3)*(1 - 3*x - 2*x^2 - 3*x^3)). - _Colin Barker_, Nov 01 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 ..1....1....0....0....1....1....0....1....0....1....1....1....1....0....1....0
%e ..2....0....1....1....0....2....0....1....0....2....0....0....0....0....0....1
%e ..2....2....0....2....0....3....1....1....1....0....1....2....2....1....1....2
%e ..3....3....0....3....2....2....2....0....0....1....0....0....3....2....1....1
%e ..0....0....0....3....0....2....3....1....2....2....2....0....2....0....1....1
%Y Column 3 of A243033.
%K nonn
%O 1,1
%A _R. H. Hardin_, May 29 2014
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