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Number of length n+2 0..9 arrays with no three elements in a row with pattern aba or abb (with a!=b) and new values 0..9 introduced in 0..9 order.
1

%I #8 Nov 02 2018 09:28:00

%S 3,5,10,25,77,280,1157,5297,26443,142372,819731,5009281,32252381,

%T 217194296,1518771097,10952508217,80950970231,609958242292,

%U 4664758144295,36080343085145,281462510140633,2209800140157400,17432715938447165

%N Number of length n+2 0..9 arrays with no three elements in a row with pattern aba or abb (with a!=b) and new values 0..9 introduced in 0..9 order.

%H R. H. Hardin, <a href="/A243518/b243518.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 30*a(n-1) - 372*a(n-2) + 2478*a(n-3) - 9639*a(n-4) + 22260*a(n-5) - 29588*a(n-6) + 20592*a(n-7) - 5760*a(n-8).

%F Empirical g.f.: x*(3 - 85*x + 976*x^2 - 5849*x^3 + 19574*x^4 - 36095*x^5 + 33305*x^6 - 11520*x^7) / ((1 - x)^2*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)*(1 - 8*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....0....1....0....1....0....1....0....1....1....0....1....1....1....1

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

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

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

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

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

%Y Column 9 of A243519.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 05 2014