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Number of length n+2 0..3 arrays with the medians of every three consecutive terms nondecreasing
1

%I #4 Nov 13 2014 10:09:43

%S 64,204,632,1959,5696,16104,45232,124249,335328,897523,2377452,

%T 6233295,16229424,41987965,107948004,276101588,703049528,1782693579,

%U 4503485124,11339512465,28466148864,71263715430,177963467480,443410709998

%N Number of length n+2 0..3 arrays with the medians of every three consecutive terms nondecreasing

%C Column 3 of A250140

%H R. H. Hardin, <a href="/A250135/b250135.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) -6*a(n-2) +24*a(n-3) -57*a(n-4) +52*a(n-5) -170*a(n-6) +256*a(n-7) -98*a(n-8) +560*a(n-9) -340*a(n-10) -80*a(n-11) -977*a(n-12) -372*a(n-13) +48*a(n-14) +624*a(n-15) +788*a(n-16) +192*a(n-17) -96*a(n-18) -288*a(n-19) -144*a(n-20)

%e Some solutions for n=6

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

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

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 13 2014