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%I #12 Apr 05 2018 03:05:27
%S 3,13,55,237,1011,4341,18567,79605,340803,1460349,6254199,26793693,
%T 114763635,491621157,2105830791,9020628261,38640044547,165518326125,
%U 709005955383,3037082133069,13009525105779,55727225184213
%N 1/16 the number of (n+1) X 3 binary arrays with no 2 X 2 subblock being a reflection across the shared element pair of any horizontal or vertical neighbor.
%C Column 2 of A183811.
%H R. H. Hardin, <a href="/A183804/b183804.txt">Table of n, a(n) for n = 1..200</a>
%F Empirical: a(n) = 3*a(n-1) + 9*a(n-2) - 15*a(n-3).
%F Empirical g.f.: x*(3 + 4*x - 11*x^2) / (1 - 3*x - 9*x^2 + 15*x^3). - _Colin Barker_, Apr 04 2018
%e Some solutions with upper left block zero for 5 X 3:
%e 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 1 0 0 1
%e 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 0 0 0 1
%e 0 1 1 1 1 1 1 1 1 1 1 0 1 1 0 1 0 0 0 1 0
%e 0 1 1 1 1 0 1 0 0 1 0 0 1 1 1 0 1 1 1 1 0
%e 1 1 0 0 1 0 0 0 1 0 0 1 0 0 1 0 1 0 1 1 1
%Y Cf. A183811.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 07 2011
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