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A209220 Number of n X 4 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 0 and 1 1 1 vertically.

%I A209220 #11 Jul 09 2018 01:43:17
%S A209220 9,81,100,196,324,576,1024,1764,3136,5476,9604,16900,29584,51984,
%T A209220 91204,160000,280900,492804,864900,1517824,2663424,4674244,8202496,
%U A209220 14394436,25260676,44328964,77792400,136515856,239568484,420414016,737774244
%N A209220 Number of n X 4 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 0 and 1 1 1 vertically.
%C A209220 Column 4 of A209224.
%H A209220 R. H. Hardin, <a href="/A209220/b209220.txt">Table of n, a(n) for n = 1..210</a>
%F A209220 Empirical: a(n) = a(n-1) + a(n-2) + a(n-3) - a(n-4) + a(n-5) - a(n-6) for n > 8.
%F A209220 Empirical g.f.: x*(9 + 72*x + 10*x^2 + 6*x^3 - 44*x^4 + 28*x^5 - 44*x^6 + 17*x^7) / ((1 - 2*x + x^2 - x^3)*(1 + x - x^3)). - _Colin Barker_, Jul 08 2018
%e A209220 Some solutions for n=4:
%e A209220   0 1 1 1     0 0 1 1     0 1 1 1     1 0 0 1     0 0 1 1
%e A209220   0 1 1 0     1 1 0 0     0 0 1 1     0 1 1 0     1 1 1 0
%e A209220   1 0 0 1     1 1 1 0     1 1 0 0     1 1 1 1     1 1 0 0
%e A209220   1 1 1 1     0 0 1 1     1 1 0 0     1 0 0 1     0 0 1 1
%Y A209220 Cf. A209224.
%K A209220 nonn
%O A209220 1,1
%A A209220 _R. H. Hardin_, Mar 06 2012