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%I #6 Apr 05 2020 21:32:48
%S 2,4,13,42,134,467,1689,6210,23178,87336,331172,1262635,4836199,
%T 18592719,71697865,277195002,1074041216,4169581090,16214541562,
%U 63150645344,246288102302,961707595682,3759467766802,14711266580343,57620439699189
%N Number of n X 2 0..1 arrays with the number of 1's horizontally or vertically adjacent to some 0 equal to the number of 0's adjacent to some 1, with top left element zero.
%C Column 2 of A284165.
%H R. H. Hardin, <a href="/A284159/b284159.txt">Table of n, a(n) for n = 1..210</a>
%e Some solutions for n=4
%e ..0..0. .0..0. .0..1. .0..1. .0..0. .0..1. .0..1. .0..1. .0..1. .0..1
%e ..0..0. .0..1. .1..0. .1..0. .0..0. .1..0. .0..1. .0..1. .0..0. .1..1
%e ..0..1. .1..1. .0..1. .1..0. .1..1. .1..1. .0..0. .0..1. .1..1. .0..0
%e ..1..1. .1..1. .1..0. .0..1. .1..1. .0..0. .1..1. .1..0. .0..1. .0..1
%Y Cf. A284165.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 21 2017