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A218898 Number of 2 X n arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random 0..1 2 X n array. 1

%I

%S 4,6,18,34,86,180,426,930,2140,4758,10818,24240,54834,123274,278260,

%T 626446,1412746,3182416,7174106,16164834,36434260,82103270,185041218,

%U 417002816,939796802,2117936730,4773120596,10756848350,24242204506

%N Number of 2 X n arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random 0..1 2 X n array.

%C Row 2 of A218897.

%H R. H. Hardin, <a href="/A218898/b218898.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) + 3*a(n-2) - 2*a(n-5).

%F Empirical g.f.: 2*x*(2 + x - x^3 - x^4) / (1 - x - 3*x^2 + 2*x^5). - _Colin Barker_, Jul 24 2018

%e Some solutions for n=3:

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

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

%Y Cf. A218897.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 08 2012

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Last modified August 5 15:17 EDT 2021. Contains 346472 sequences. (Running on oeis4.)