A183597 - OEIS

%I #9 Mar 30 2018 09:09:25

%S 120,1479,17174,201770,2366412,27768032,325834456,3823553752,

%T 44868561272,526526214848,6178727749808,72506794636336,

%U 850861000923008,9984783537547136,117170625132737568,1374987868096008576

%N 1/6 the number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock containing all three values.

%C Column 3 of A183603.

%H R. H. Hardin, <a href="/A183597/b183597.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 12*a(n-1) + 20*a(n-2) - 238*a(n-3) - 420*a(n-4) + 324*a(n-5) + 400*a(n-6) - 224*a(n-7).

%F Empirical g.f.: x*(120 + 39*x - 2974*x^2 - 5338*x^3 + 4094*x^4 + 5400*x^5 - 3024*x^6) / (1 - 12*x - 20*x^2 + 238*x^3 + 420*x^4 - 324*x^5 - 400*x^6 + 224*x^7). - _Colin Barker_, Mar 30 2018

%e Some solutions with a(1,1)=0 for 3 X 4:

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

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

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

%Y Cf. A183603.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 05 2011