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%I #9 Apr 15 2018 07:57:48
%S 424,8272,108496,1792144,27993232,454774672,7339536784,119205236368,
%T 1934859805840,31437977902480,510797840746384,8300795694017680,
%U 134894624057920144,2192213833325394832,35626484733088902544
%N Number of (n+1) X 3 0..3 arrays with every 2 X 2 subblock singular.
%C Column 2 of A184773.
%H R. H. Hardin, <a href="/A184766/b184766.txt">Table of n, a(n) for n = 1..200</a>
%F Empirical: a(n) = 20*a(n-1) - 19*a(n-2) - 792*a(n-3) + 1800*a(n-4).
%F Empirical g.f.: 8*x*(53 - 26*x - 6111*x^2 + 14400*x^3) / (1 - 20*x + 19*x^2 + 792*x^3 - 1800*x^4). - _Colin Barker_, Apr 15 2018
%e Some solutions for 5 X 3:
%e ..0..0..0....2..0..0....0..0..0....0..0..0....2..0..0....2..0..0....2..0..0
%e ..2..0..1....0..0..0....0..0..3....2..3..1....0..0..3....0..0..2....2..0..2
%e ..1..0..2....0..0..1....0..0..0....0..0..0....2..0..0....0..0..0....3..0..3
%e ..1..0..1....2..0..3....2..2..2....2..0..1....2..0..2....0..0..0....0..0..2
%e ..1..0..0....0..0..1....2..2..2....2..0..0....3..0..0....3..2..1....1..0..2
%Y Cf. A184773.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 21 2011
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