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Number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock sum greater than 4.
1

%I #9 Apr 12 2018 22:24:28

%S 31,165,792,3971,19593,97312,482071,2390621,11850280,58751643,

%T 291260673,1443961520,7158542031,35489140405,175940409400,

%U 872240066291,4324205636281,21437626315584,106278895767879,526886873434445

%N Number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock sum greater than 4.

%C Column 1 of A184497.

%H R. H. Hardin, <a href="/A184489/b184489.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 3*a(n-1) + 11*a(n-2) - 4*a(n-3) - 12*a(n-4).

%F Empirical g.f.: x*(31 + 72*x - 44*x^2 - 96*x^3) / ((1 + 2*x)*(1 - 5*x - x^2 + 6*x^3)). - _Colin Barker_, Apr 12 2018

%e Some solutions for 3 X 2:

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

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

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

%Y Cf. A184497.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 15 2011