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%I #9 Jun 07 2018 08:05:03
%S 891,713,622,704,1264,2956,6772,17852,48260,129860,354004,966724,
%T 2637700,7205348,19685060,53774276,146912644,401372740,1096558660,
%U 2995851716,8184819524,22361319236,61092256324,166907149636,455998766404
%N Number of (n+2) X 6 0..2 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..2 introduced in row major order.
%C Column 4 of A204370.
%H R. H. Hardin, <a href="/A204366/b204366.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) -6*a(n-4) +4*a(n-6) for n>9.
%F Empirical g.f.: x*(891 - 1960*x - 1517*x^2 - 1162*x^3 + 4498*x^4 + 3442*x^5 - 1928*x^6 - 1092*x^7 - 200*x^8) / ((1 - x)*(1 - 2*x - 2*x^2)*(1 - 2*x^3)). - _Colin Barker_, Jun 07 2018
%e Some solutions for n=5:
%e ..0..0..1..1..1..2....0..0..0..0..0..0....0..0..1..1..1..2....0..0..0..0..1..0
%e ..0..0..0..1..1..1....1..1..1..1..1..1....0..0..0..1..1..1....1..1..1..1..1..1
%e ..1..0..0..0..1..1....2..2..2..2..2..2....1..0..0..0..1..1....1..1..1..1..1..1
%e ..1..1..0..0..0..1....1..1..1..1..1..1....1..1..0..0..0..1....0..0..0..0..0..0
%e ..1..1..1..0..0..0....0..0..0..0..0..0....1..1..1..0..0..0....2..2..2..2..2..2
%e ..0..1..1..1..0..0....2..2..2..2..2..2....2..1..1..1..0..0....2..2..2..2..2..2
%e ..2..2..1..1..1..0....2..2..2..2..2..2....2..0..1..1..1..0....0..2..0..0..0..0
%Y Cf. A204370.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 14 2012
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