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%I #7 Jul 23 2018 09:57:38
%S 4,16,50,130,296,624,1289,2741,6134,14269,33577,78304,179671,406765,
%T 915275,2061311,4664237,10605587,24181837,55152622,125626530,
%U 285683099,648937238,1473615534,3347303199,7607369029,17296530794,39333312344
%N Number of n element 0..3 arrays with each element the minimum of 4 adjacent elements of a random 0..3 array of n+3 elements.
%C Column 4 of A217954.
%H R. H. Hardin, <a href="/A217950/b217950.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) + 6*a(n-5) - 4*a(n-6) + 6*a(n-7) + 4*a(n-8) + 5*a(n-9) + a(n-10) + 3*a(n-11) + 2*a(n-12) + a(n-13).
%F Empirical g.f.: x*(1 - x + x^2)*(2 + 2*x + x^2)*(2 + 4*x^2 + 4*x^3 + 5*x^4 + 2*x^5 + 3*x^6 + 2*x^7 + x^8) / (1 - 4*x + 6*x^2 - 4*x^3 + x^4 - 6*x^5 + 4*x^6 - 6*x^7 - 4*x^8 - 5*x^9 - x^10 - 3*x^11 - 2*x^12 - x^13). - _Colin Barker_, Jul 23 2018
%e Some solutions for n=4:
%e ..0....1....2....0....0....0....1....1....1....2....1....3....3....2....2....2
%e ..0....1....3....1....2....2....3....1....3....2....3....3....3....2....1....2
%e ..3....1....3....0....2....1....3....1....0....2....1....0....3....3....1....0
%e ..1....3....2....0....1....0....0....2....0....2....0....0....0....1....1....0
%Y Cf. A217954.
%K nonn
%O 1,1
%A _R. H. Hardin_, Oct 15 2012
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