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%I #6 Aug 12 2016 06:54:16
%S 0,2,3,11,29,93,268,842,2547,7946,24539,76721,239462,751569,2360679,
%T 7437243,23461543,74155431,234687456,743792675,2359972537,7496293462,
%U 23834595755,75852059135,241594260984,770090455545,2456436981617
%N Number of 2Xn arrays containing n copies of 0..2-1 with every element equal to at least one horizontal or vertical neighbor and the top left element equal to 0.
%C Row 2 of A267901.
%H R. H. Hardin, <a href="/A267902/b267902.txt">Table of n, a(n) for n = 1..210</a>
%e Some solutions for n=4
%e ..0..1..0..1....0..0..1..1....0..1..1..1....0..0..1..0....0..0..0..1
%e ..0..1..0..1....1..1..0..0....0..0..0..1....1..1..1..0....1..1..0..1
%Y Cf. A267901.
%K nonn
%O 1,2
%A _R. H. Hardin_, Jan 22 2016
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