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A217451 Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal and vertical neighbors in a random 0..2 n X 2 array. 2

%I

%S 3,15,69,253,1049,4205,16887,68015,273471,1100135,4425449,17801365,

%T 71607677,288046417,1158686263,4660895899,18748771139,75418217399,

%U 303374944277,1220346484777,4908927310389,19746496259789,79431633434755

%N Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal and vertical neighbors in a random 0..2 n X 2 array.

%C Column 2 of A217457.

%H R. H. Hardin, <a href="/A217451/b217451.txt">Table of n, a(n) for n = 1..128</a>

%F Empirical: a(n) = 3*a(n-1) + 3*a(n-2) + 6*a(n-3) - 5*a(n-4) + a(n-5) - 17*a(n-6) - 14*a(n-7) - 26*a(n-8) - 4*a(n-9).

%F Empirical g.f.: x*(3 + 6*x + 15*x^2 - 17*x^3 + 8*x^4 - 43*x^5 - 12*x^6 - 62*x^7 - 12*x^8) / (1 - 3*x - 3*x^2 - 6*x^3 + 5*x^4 - x^5 + 17*x^6 + 14*x^7 + 26*x^8 + 4*x^9). - _Colin Barker_, Mar 09 2018

%e Some solutions for n=3:

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

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

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

%Y Cf. A217457.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 03 2012

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Last modified October 21 21:25 EDT 2021. Contains 348155 sequences. (Running on oeis4.)