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Number of n element 0..2 arrays with each element the minimum of 5 adjacent elements of a random 0..2 array of n+4 elements.
1

%I #9 Jul 23 2018 08:45:33

%S 3,9,22,46,86,148,244,402,685,1223,2263,4243,7910,14528,26274,47012,

%T 83787,149619,268568,484722,878014,1592150,2884434,5215660,9413514,

%U 16970286,30584282,55140634,99481417,179592631,324338478,585786560

%N Number of n element 0..2 arrays with each element the minimum of 5 adjacent elements of a random 0..2 array of n+4 elements.

%C Column 5 of A217883.

%H R. H. Hardin, <a href="/A217880/b217880.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + 3*a(n-6) - a(n-7) + a(n-8) + a(n-9) + a(n-10) + a(n-11).

%F Empirical g.f.: x*(1 + x^2 + x^3 + x^4 + x^5)*(3 + x^2 + x^3 + x^4 + x^5) / ((1 - x + x^3 + x^4 + x^5)*(1 - 2*x + x^2 - x^3 - x^6)). - _Colin Barker_, Jul 23 2018

%e Some solutions for n=4:

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

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

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

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

%Y Cf. A217883.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 14 2012