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A185514 Number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock singular. 1

%I

%S 143,1489,12361,115979,1058503,9856209,91539073,853020411,7948563615,

%T 74110312433,691029158489,6444134240459,60095780277207,

%U 560446106259121,5226693550531025,48744151344694907,454588941498687343

%N Number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock singular.

%C Column 2 of A185521.

%H R. H. Hardin, <a href="/A185514/b185514.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 12*a(n-1) - 11*a(n-2) - 154*a(n-3) + 224*a(n-4).

%F Empirical g.f.: x*(143 - 227*x - 3934*x^2 + 6048*x^3) / (1 - 12*x + 11*x^2 + 154*x^3 - 224*x^4). - _Colin Barker_, Apr 16 2018

%e Some solutions for 5 X 3:

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

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

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

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

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

%Y Cf. A185521.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 29 2011

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Last modified May 19 23:40 EDT 2022. Contains 353847 sequences. (Running on oeis4.)