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A229639 Number of defective 3-colorings of a 3 X n 0..2 array connected horizontally, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.

%I A229639 #7 Apr 27 2021 22:21:02
%S A229639 0,39,244,1109,6031,28448,136778,633328,2905016,13118016,58633648,
%T A229639 259523840,1139461984,4967050352,21516000592,92679568016,397212173264,
%U A229639 1694694809008,7200709256752,30481238674128,128588345884944
%N A229639 Number of defective 3-colorings of a 3 X n 0..2 array connected horizontally, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.
%C A229639 Row 3 of A229637.
%H A229639 R. H. Hardin, <a href="/A229639/b229639.txt">Table of n, a(n) for n = 1..210</a>
%F A229639 Empirical: a(n) = 9*a(n-1) - 15*a(n-2) - 51*a(n-3) + 96*a(n-4) + 138*a(n-5) - 92*a(n-6) - 60*a(n-7) +4 8*a(n-8) - 8*a(n-9) for n > 12.
%e A229639 Some solutions for n=3:
%e A229639   0 1 1   0 0 1   0 1 2   0 1 0   0 1 0   0 1 0   0 1 2
%e A229639   2 1 0   1 2 1   0 1 0   1 2 1   2 1 0   2 1 0   0 1 2
%e A229639   2 1 0   1 0 0   1 2 1   1 0 1   1 1 0   1 2 0   1 0 2
%K A229639 nonn
%O A229639 1,2
%A A229639 _R. H. Hardin_, Sep 27 2013