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A297860 Number of n X 2 0..1 arrays with every element equal to 2, 3 or 4 king-move adjacent elements, with upper left element zero. 4

%I

%S 0,1,2,5,10,25,54,125,282,641,1454,3301,7490,17001,38582,87565,198730,

%T 451025,1023614,2323125,5272402,11965881,27156934,61633501,139879130,

%U 317460001,720485262,1635163525,3711054050,8422351625,19114786774

%N Number of n X 2 0..1 arrays with every element equal to 2, 3 or 4 king-move adjacent elements, with upper left element zero.

%C Column 2 of A297866.

%H R. H. Hardin, <a href="/A297860/b297860.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-2) + 4*a(n-3) + 2*a(n-4).

%F Empirical g.f.: x^2*(1 + 2*x + 2*x^2) / ((1 + x)*(1 - x - 2*x^2 - 2*x^3)). - _Colin Barker_, Feb 21 2018

%e Some solutions for n=7:

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

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

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

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

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

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

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

%Y Cf. A297866.

%K nonn

%O 1,3

%A _R. H. Hardin_, Jan 07 2018

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Last modified August 5 21:18 EDT 2020. Contains 336213 sequences. (Running on oeis4.)