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Number of arrays of the median of three adjacent elements of some length -(n+2) 0..3 array.
1

%I #13 Sep 02 2013 13:02:51

%S 4,16,64,232,696,2072,6130,18378,55716,169734,517764,1578184,4806344,

%T 14629384,44519552,135480532,412314438,1254882280,3819338704,

%U 11624541548,35380360780,107682931160,327740673246,997501106370,3035962621026

%N Number of arrays of the median of three adjacent elements of some length -(n+2) 0..3 array.

%H R. H. Hardin, <a href="/A228735/b228735.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) -2*a(n-2) -6*a(n-3) +6*a(n-4) +15*a(n-5) -11*a(n-6) +a(n-7) +a(n-8) +3*a(n-9) +24*a(n-10) -3*a(n-11) -35*a(n-12) -28*a(n-13) +22*a(n-14) +18*a(n-15) -9*a(n-16) -11*a(n-17) -4*a(n-18) +15*a(n-19) +15*a(n-20) -2*a(n-21) -4*a(n-22) -4*a(n-23) -3*a(n-24) +a(n-25) +a(n-26)

%e Some solutions for n=4

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

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

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

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

%Y Column 3 of A228740.

%K nonn

%O 1,1

%A _R. H. Hardin_ Sep 01 2013