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Number of length n+2 0..8 arrays with no three elements in a row with pattern aba or abb (with a!=b) and new values 0..8 introduced in 0..8 order.
1

%I #8 Nov 02 2018 12:25:20

%S 3,5,10,25,77,280,1157,5296,26406,141585,807064,4837587,30181075,

%T 194210670,1279159631,8571132698,58153599684,398124806735,

%U 2743173705258,18987825983429,131858977691833,917797527716980,6398758306106345

%N Number of length n+2 0..8 arrays with no three elements in a row with pattern aba or abb (with a!=b) and new values 0..8 introduced in 0..8 order.

%H R. H. Hardin, <a href="/A243517/b243517.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 23*a(n-1) - 212*a(n-2) + 1010*a(n-3) - 2669*a(n-4) + 3887*a(n-5) - 2878*a(n-6) + 840*a(n-7).

%F Empirical g.f.: x*(3 - 64*x + 531*x^2 - 2175*x^3 + 4579*x^4 - 4607*x^5 + 1680*x^6) / ((1 - x)^2*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 7*x)). - _Colin Barker_, Nov 02 2018

%e Some solutions for n=5:

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

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

%e ..2....2....2....2....2....2....1....0....0....2....2....2....0....2....2....2

%e ..3....3....3....3....3....3....2....0....0....0....3....3....1....0....3....3

%e ..4....1....0....0....0....0....3....0....0....3....4....1....2....3....1....4

%e ..5....0....1....4....2....2....0....1....0....4....1....0....3....4....2....1

%e ..0....4....3....5....1....4....4....2....0....2....3....2....4....0....3....5

%Y Column 8 of A243519.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 05 2014