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%I #8 Sep 21 2018 08:14:01
%S 210,20032,41872,69198,113330,186396,314700,557578,1046550,2070144,
%T 4258696,8984046,19221426,41402836,89392212,192991026,416096878,
%U 895389192,1922585088,4119014998,8805491466,18784661532,39993300364
%N Number of defective 4-colorings of an n X 7 0..3 array connected horizontally, vertically, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..3 order.
%H R. H. Hardin, <a href="/A229754/b229754.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 9*a(n-1) - 33*a(n-2) + 63*a(n-3) - 66*a(n-4) + 36*a(n-5) - 8*a(n-6) for n>11.
%F Empirical g.f.: 2*x*(105 + 9071*x - 65743*x^2 + 170088*x^3 - 187916*x^4 + 63288*x^5 + 30816*x^6 - 21756*x^7 - 2936*x^8 + 504*x^9 + 1360*x^10) / ((1 - x)^3*(1 - 2*x)^3). - _Colin Barker_, Sep 21 2018
%e Some solutions for n=3:
%e ..0..1..0..0..2..0..1....0..1..0..2..3..0..1....0..1..0..2..3..2..1
%e ..2..3..2..3..1..3..2....2..3..3..1..1..2..3....3..2..3..1..0..1..3
%e ..1..0..2..0..2..0..1....0..1..2..0..3..0..1....0..1..0..2..3..2..1
%Y Column 7 of A229755.
%K nonn
%O 1,1
%A _R. H. Hardin_, Sep 28 2013
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